A Novel Light trapping for high efficiency a-Si:H/ μc-Si Micromorph tandem Solar Cells

A Novel Light trapping for high efficiency a-Si:H/ μc-Si Micromorph tandem Solar Cells | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Novel Light trapping for high efficiency a-Si:H/ μc-Si Micromorph tandem Solar Cells Ramisa Eghbali, Saeed Khosroabadi, Anis Shokouhmand This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2268259/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The performance of a-Si:H/μc-Si:H tandem solar cell has been studied by using two-dimensional numerical simulation. In this work, after optimizing the thicknesses of each layer, light trapping techniques have been investigated to increase the photogenerated current in both sub cells. 1D- photonic crystal has been implemented as a broadband back reflector in a solar cell while to reduce the reflection from the surface of the top cell, two-layer anti-reflection, SiO 2 /Si 3 N 4 has been suggested. In order to match the current density of sub cells as well as prevent the accumulation of carries in its interface, Tunnel Recombination Junction is required in the interlayer. Here, we have used n-μc-Si:H /p-μc-Si:H with a thickness of 10nm as a TRJ. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.38 V, a short-circuit current density of 12.51 mA/cm 2 , and a fill factor of 80.82%, corresponding to a total area conversion efficiency of 14%. Micromorph Solar cell Tunnel Recombination Junction Light trapping a-Si:H Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 1 Introduction Multi-junction structures in thin-film technology are generally suggested as a practical solution for reducing loss mechanisms and achieving more efficient utilization of the solar spectrum to improve the collection of photogenerated carriers [1]. One of the major loss mechanisms limiting solar cell performance is the thermalization effect [2] which means a significant part of Photon energy is turned into heat due to the difference between photon energy and electronic bandgap, Eg, of the absorber material. The simplest multi-junction structure is made of two sub cells in which the top cell has a higher band gap in comparison with the bottom cell. Consequently, photons with low energy, hυ < Eg, which cannot be absorbed in the top layer transmitted to the bottom cell and then absorbed there. Owning to its nontoxicity, abundance of raw materials, and low-cost manufacturing [3], thin-film solar cell based on hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si:H) as absorber layers has attracted more attention. However, a-Si:H solar cell has two major problems that should be addressed. The first one is a short diffusion length of minority carriers in the absorber layer [4]. The second is light-induced degradation due to the Staebler-Wronski effect [5]. Although, implementing thinner absorber layer partly mitigates these issues, it leads to lower efficiency due to lower generated current. Therefore, the thickness of the absorber layer a-Si:H is limited to a few hundred nanometers. In order to improve the efficiency of the hydrogenated amorphous silicon solar cells, tandem, Micromorph, cells have been manufactured [6]. Micromorph solar cell is the combination of a-Si:H, with a band gap of ~1.8 ev and μc-Si, with a band gap of ~1.1 ev as a top and bottom layers respectively. Theoretically, as the sub cells are connected in series in tandem solar cell, the sub cell which produces less electron-hole pairs restrict the total current of tandem solar cells. There is no doubt that the top cell, a-Si:H, determines the total current density in Micromorph. The prime target to reach the maximum efficiency in Micromoph solar cell is to enhance the current density which can be achievable by increasing the optical path length of the incident light [7] and enhancing the light absorption in intrinsic layers with given thicknesses. Advanced light management should be used to improve efficiency. Since amorphous Silicon has a high refractive index, a significant part of incident light is reflected from the surface of the cell. The utilization of anti-reflection coating, ARC on the surface of a solar cell can partly recover this problem. In 2011, Experimental studies have been demonstrated that AR/glass/transparent conducting oxide (TCO)/active layers lead to about 3% reduction of the reflectance (over the 350–1100 nm range) at the air/glass interface. Therefore, the absorption of light in the active layer is enhanced [8]. In [7] simulated and measured results of using ZnO:Al and SnO2:F as an ARC are shown. In [9] novel double-layered antireflection coatings have been experimented. Another method for enhancing the light absorption is inserting a high-reflectivity material at the backside, as this can deliberately avoid escaping light from the backside of cells and reflect it into the cell. The influence of back reflectors on the Micromorph performance has been widely simulated and measured in [10, 11]. The conventional back reflector is Silver coated with ZnO [12-15]. One-Dimensional Photonic Crystal, 1DPC, as a back reflector used in amorphous and microcrystalline thin film silicon solar cells to increase the absorption [16-18]. A new concept of a modulated one-dimensional photonic-crystal (PC) structure has been introduced by [19] as a back reflector for thin-film solar cells. Carrier accumulation between the n-layer of a-Si:H and p-Layer of μc-Si can lead to the deterioration of the cell performance [18]. To enhance the recombination rate, electron in n-layer of top cell and the hole in p-layer of the bottom cell, a layer with high conductivity as well as transparent should be implemented between top and bottom cells. In [20] ZnO not only acts as a connector but also is a transparent oxide that can easily transfer light to bottom cell. Another suggestion for interlayer is Tunnel recombination junction, TRJ which could reduce the carrier accumulation [1, 21]. Besides, using a three-dimensional photonic crystal (3D-PC) between the top and bottom cells in Micromorph tandem solar cells has been reported [22]. In this paper, we will closely study three different parts of tandem solar cell, front side, intermediate layer between sub cells and backside of cells, by light management techniques to enhance light absorption in both top and bottom cells. A high-efficiency Micromorph solar cell will be proposed through these investigations. In comparison to previous simulated works, our proposed configuration is a result of comprehensive research in which each important part of tandem cell separately investigated and optimized. In addition, optical and electrical parameters used for simulation are taken from the valid experimental study [21, 23], so that the same results prove our simulation have been conducted perfectly. The body of the paper is organized as follows: first, we will discuss numerical models used in the simulation of Micromorph solar cell. And then the simulation studies are performed on two single solar cell, a-Si:H and μc-Si:H, individually. We will introduce our reference structure which is based on experimental previous work. We will follow this section by utilizing different advanced light trapping methods. We suggest our proposed structure with improved efficiency. Finally, we will close the paper in section 3 with the conclusion. 2 Numerical Models In this work, Shockley-Read-Hall recombination as a physical model is used to describe the recombination mechanisms in both (p-i-n) a-Si:H and (p-i-n) µc-Si:H cells while for interlayer TRJ, trap-assisted tunneling recombination model could be well-defined. The physical model used for mobility is concentration-dependent low-field mobility model. Disordered Hydrogen and silicon atoms and its amorphous nature introduce many defect states, dangling which is modeled by the Defect Pool Model [21]. For this simulation, the indices of refraction are modeled as having a dependence on wavelength. The tandem solar cell operates under the global standard spectrum, AM 1.5 at a temperature of 300K. 3 Simulations and Results 3.1. Single a-Si:H Solar cell As it is shown in Fig.1, in the first step single amorphous silicon solar cell consists of ZnO/p-a-Si:H(13 nm)/i-a-Si:H(220 nm)/n-a-Si:H(20 nm)/ZnO/Silver/Al [21] is simulated. Electrical parameters used in the simulation are given in Table.1 and Defect details values are taken from the literature [21]. Here, the intrinsic layer located between p-doped and n-doped layers acts as an absorber layer. For front electrical contact, ZnO is chosen while ZnO/Ag/Al layer is responsible for a back reflector. According to Fig.2 and 3, output parameters obtained from simulation of the cell are as follows: J SC =14.32mA/cm 2 , V OC =0.9 V, fill factor (FF) =82.15% and conversation efficiency (η) =10.62%. Table 1. Electrical Parameters of the proposed structure Layar properties a-Si:H (top cell) μc-Si:H (TRJ) μc-Si:H (bottom cell) P i n n P P i n Thickness (nm) 13 220 20 5 5 20 2500 15 N D (cm -3 ) - - 10 20 10 20 - - - 10 20 N A (cm -3 ) 3×10 19 - - - 3×10 19 10 20 - - E g (eV) 1.71 1.71 1.71 1.16 1.16 1.16 1.16 1.16 N C (cm -3 ) 10 21 10 21 10 21 3.5×10 20 3.5×10 20 3.5×10 20 3.5×10 20 3.5×10 20 N V (cm -3 ) 10 21 10 21 10 21 3.5×10 20 3.5×10 20 3.5×10 20 3.5×10 20 3.5×10 20 c (eV) 3.89 3.89 3.89 4.05 4.05 4.05 4.05 4.05 e 11.9 11.9 11.9 11.9 11.9 11.9 11.9 11.9 m e (cm 2 /V s ) 1 1 1 20 20 20 20 20 m h (cm 2 /Vs) 0.6 0.6 0.6 4 4 4 4 4 3.2. Single μc-Si:H Solar cell Here, the single configuration of μc-Si:H solar cell is exactly the same as Single a-Si:H, although, the former has a thicker intrinsic layer, Fig. 4. The thickness of each layer in this structure are p-µc-Si:H (20 nm) / i-µc-Si:H (2500 nm)/ n-µc-Si:H (15 nm) that are adopted from the literature [21]. Electrical parameters are taken from the simulation are J SC =20.1mA/cm 2 , V OC =0.4V, fill factor (FF) =66.97% and conversation efficiency (η) =5.31%. J-V curves and Quantum Efficiency are shown in Fig. 5 and Fig. 6 respectively. 3.3. a-Si:H/ µc-Si:H Tandem Solar cell In this section, we have proposed a reference structure of Micromoph Solar cell which is depicted in Fig.7. At the front side, ZnO as a transparent conductive oxide with thickness of 40 nm is used while the combination of ZnO (40 nm)/Ag (100 nm)/Al (200 nm) acts as a Back Reflector in the back side of solar cell. To improve the recombination of the carrier between sub cells, Tunnel Recombination Junction, TRJ, which includes the simple n-μc-Si:H and p-μc-Si:H is suggested. In fact, by tunneling mechanism, holes generated in the bottom cell can be recombined with electrons generated in the top cell in the interface of TRJ due to localized trap states in this area. Here, in order to find optimum TRJ thicknesses, the electrical behavior of solar cell by altering the thickness of TRJ layer has been studied. As simulated Efficiency is shown Fig. 8, by decreasing the thickness of TRJ layer, both layers, the total current density of structure is increased due to high recombination rate in the interlayer. It is obvious by enhancing the current density; efficiency is improved to 12.22%. Based on the simulation demonstrated in Fig. 8, thicknesses TRJ of both n-μc-Si:H and p-μc-Si:H are chosen by 5 nm. As a result, electrical parameters of solar cell will be J SC =11mA/cm 2 , V OC =1.35V, fill factor (FF) =81.92% and conversation efficiency (η) =12.22%. Fig 9 shows Electrical results of solar cell. 3.4. Reference Solar cell with proposed Anti-Reflector As mentioned, for lowering the reflection of light from the surface of solar cell, Anti reflector on front side of the cell is normally utilized. Since the used solar spectrum for single-junction solar cells is relatively small, for example, 300-700 nm for a-Si:H solar cells, a single-layer anti reflector like SiO 2 with the thickness of a quarter wavelength is acceptable. However, Multi-junction solar cells such as Micromorph require ARC which is able to transfer most parts of the wide solar spectrum. Here, we introduce a two-layer ARC which is composed of SiO 2 , Si 3 N 4 layers with thicknesses of 230 nm and 55 nm respectively. As it is shown in Fig. 10, more than 90% of light could transfer into the Micromorph through proposed Anti-Reflection coating in wavelength 300-1000 nm. The Micromoph with ARC is demonstrated in Fig. 11. As it is expected, by adding ARC on the surface of Micromorph, absorption of light increased which causes improvement in J SC . While open Circuit Voltage remains nearly unchanged, short circuit current reaches 12.093 mA/ cm 2 from 11 mA/ cm 2 and so efficiency increases to 13.29%. Fig. 12 shows the J-V and PV characteristics of Micromorph with ARC. 3.5. a-Si:H/ µc-Si:H Tandem Solar cell with proposed DBR A significant part of the incident light, mostly in the Infrared region, is not able to be absorbed in the intrinsic layer of a-Si:H due to thin thickness and partly absorbed in µc-Si:H bottom cell. A conventional light-trapping method is Silver coated with Zno, ZnO/Ag coating as back reflector basically suffers from intrinsic losses from surface plasmon modes generated at the metal-dielectric interface [13-15]. The photonic crystals could ideally reflect near 100 % light over a specific wavelength band [18]. Here, the combination of Ag/AL is replaced with 1D- photonic crystal, known as Distributed Bragg Reflector, DBR. 1D- photonic crystal is the structure with two different materials with different thicknesses (d 1 , d 2 ) and refractive indices (n1, n2) are stacked periodically in one fixed direction. By selecting appropriate materials with larger n1/n2 ratio, the higher reflectance around central wavelength (λ Β ) will be achieved. In addition, it is required that reflectance bandwidth, known forbidden gap in PC, should be wide, as this can reflect back entire light in solar spectrum into the cell. In order to achieve maximum reflectance in the range of 700-1200 nm for Micromorph solar cell, Si (n 1 =3.36 at λ=600 nm) and SiO 2 (n 2 =1.48 at λ=600 nm) are chosen. Silicon thickness is calculated 47 nm in the central wavelength, λ Β , based on PC formula below: After optimizing the DBR structure, four pair of layers Si/SiO 2 with thicknesses of d 1 , =57nm and d 2 =138 nm, has been suggested, Fig. 13. As it is depicted in Fig. 14, by rising the number of pairs, more than 95% of light can be reflected in wavelength 600-1200nm. In this way, the distance that light should travel will increase. As a result, by using light trapping, a considerable part of light has been absorbed by solar cell, particularly in the bottom sub cell. Although, one pair DBR has a broader wavelength, normalized reflectance is less than 60%. Moreover, in designing DBR as a back reflector, the main goal is to increase the absorption in long wavelength around 1200nm which four pairs can meet this target. Fig. 15 demonstrates the efficiency of Micromorph solar cell by using different pairs of DBR. As it is expected, when one pair of PC is utilized, efficiency will be 10.29, while the calculated parameter is around 13.68% when a four-pair layer is inserted in the back of solar cell, Fig. 16. Current density and power density characteristics of a-Si:H/ µc-Si:H Tandem Solar cell with proposed DBR is shown in Fig. 17. In comparison of Zno/Ag/Al as a Back Reflector, Zno/DBR increases the current density 12.27 mA/cm 2 while V OC and Fill Factor (FF) will be 1.36 and 82.15%, respectively. 3.6. Modification of Doping in Proposed Micromorph In this part, by incorporating all TRJ, SiO 2 /Si 3 N 4 and 1DPC in the Micromorph solar cell, the efficiency of the final configuration improved. Fig. 18 shows the proposed a-Si:H/ µc-Si:H tandem solar cell. According to the simulation, efficacy of the final solar cell reaches 13.71% after performing advanced light trapping. By adding uniform impurity concentration to p-a-Si:H and n layer of TRJ could gain 14% of conversion efficiency. The impurity of p-a-Si:H and n layer of TRJ have been selected 4×10 20 cm -3 and 2×10 20 cm -3 respectively. The simulated values for the electrical characteristics are J SC =12.51mA/cm 2 , V OC =1.38 V, FF=80.82% and 𝜂=14%. J-V and P-V characteristics of proposed a-Si:H/ µc-Si:H tandem solar cell is shown in Fig. 19. Figs. 20 and 21 compare the electrical and optical characteristics of the Micromorph solar cell for various structures added to cell, separately. As these figures show, there is a considerable improvement in quantum efficiency especially in the bottom cell; this enhancement is clearly depicted in J-V as well as P-V curves. Utilizing advanced light management shows that current density improved while open circuit voltage stayed certain. Table 2 shows a comparison of the proposed structure with works reported in the past few years. As one can see the result of simulation of the proposed structure is acceptable and nearly to close to experimental results. Table 2. Electrical Parameters of the proposed structure Work J SC ( mA/cm 2 ) V OC (v) FF Eff Ref [23] 13.45 1.342 70.2 12.29-13 Ref [3] 13.69 1.391 71.7 13.65 Ref [24] 10.79 1.42 69.58 10.655 Ref [25] 12.45 1.33 72 11.92 Ref [26] 11.74 1.38 67.21 12.6 This Work 12.51 1.38 80.82 14 4 Conclusion In this paper, we have conducted three methods to develop photon absorption in top and bottom cells of Micromorph solar cell. TRJ is an effective way to improve recombination rate in interface of sub cells. Anti-reflection coating utilized on the top cell causes that current density about 9% increases. As a result, conversion Efficient reaches 13.29%. Moreover, by incorporating DBR in the backside of Micromorph, current 12.27 mA/cm 2 increases. Doping modification and applying all of mentioned proposed light trapping methods in Micromorph solar cell shows a significant improvement compared to reference cell. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.38 V, a short-circuit current density of 12.51 mA/cm 2 , and a fill factor of 80.82%, corresponding to a total area conversion efficiency of 14%. Declarations Funding statement This paper is not financially supported by any organizations and institutions. Ethics approval The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflict of Interest The authors declare that there is no conflict of interest reported in this paper. Authors' contributions All the works in this paper (study conception and design, material preparation, data collection and analysis) have done together by Ramisa Eghbali, Saeed Khosroabadi and Anis Shokouhmand. All authors read and approved the final manuscript. Code Availability Not applicable. Consent to Participate All authors voluntarily agree to participate in this research study. Consent for Publication All authors have endorsed the publication of this research. Availability of data and material The data and material are available within the manuscript. Acknowledgements Not applicable. References Madaka, R., Kumar, D., Singh, A. K., Uddin, M. S., & Rath, J. K. (2021). Tunnel recombination junction influence on the a-Si: H/SHJ tandem solar cell. Mater Today Proc, 39: 1970-1973. Fahr, S., Rockstuhl, C., & Lederer, F. (2010). Improving the efficiency of thin film tandem solar cells by plasmonic intermediate reflectors. Photonics Nanostruct, 8: 291-296. 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University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Anis","middleName":"","lastName":"Shokouhmand","suffix":""}],"badges":[],"createdAt":"2022-11-13 10:44:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2268259/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2268259/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":29144967,"identity":"e351f38d-61cc-4a56-be2d-5880f0807131","added_by":"auto","created_at":"2022-11-16 16:02:50","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":27984,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of the simulated single a-Si:H Solar Cell.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/a36cb8001c973022501c3c21.png"},{"id":29144224,"identity":"26b26895-ecb6-4f2a-b537-1e2fbdbeebda","added_by":"auto","created_at":"2022-11-16 15:54:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":52634,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V characteristics of single a-Si:H Solar cell.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/5a85c4868b14d81e957ec526.png"},{"id":29144176,"identity":"0e73b84d-0344-4708-9574-94934dc0714f","added_by":"auto","created_at":"2022-11-16 15:54:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":60007,"visible":true,"origin":"","legend":"\u003cp\u003eQuantum Efficiency of single a-Si:H Solar cell.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/f7bcd0d7d0cbb5152a1263cc.png"},{"id":29144179,"identity":"d00659d6-d859-4829-9f28-ecb60b770a2a","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":36032,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of the simulated Single µc-Si:H Solar Cell.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/1b562e9a069752e7a2ed9028.png"},{"id":29144175,"identity":"01e02a2e-d6e3-4f33-955d-bdd4037c29d7","added_by":"auto","created_at":"2022-11-16 15:54:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":56864,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V characteristics of single µc-Si:H Solar cell.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/f0a2f9266d7e60f3dcd13665.png"},{"id":29144233,"identity":"5d783019-1ee9-42c3-8874-4d165aa37aef","added_by":"auto","created_at":"2022-11-16 15:54:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":57997,"visible":true,"origin":"","legend":"\u003cp\u003eQuantum Efficiency of single µc-Si:H Solar cell.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/49335605e79681eec3cebafd.png"},{"id":29144174,"identity":"f42acc10-98f4-4d3c-ae56-ebf7b4a9d838","added_by":"auto","created_at":"2022-11-16 15:54:48","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":93219,"visible":true,"origin":"","legend":"\u003cp\u003eThe schematic structure of a-Si:H/µc-Si:H Tandem Solar cell.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/df4174c772048f1d6b896494.png"},{"id":29144222,"identity":"382b6c8e-b090-45f1-999e-5828b176c268","added_by":"auto","created_at":"2022-11-16 15:54:53","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":53522,"visible":true,"origin":"","legend":"\u003cp\u003eEfficiency as a function of TRJ layer thickness.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/b597ca8c0bf1d4a304de5ed6.png"},{"id":29144184,"identity":"8d82118b-044f-42c7-9b83-71de88b1da7a","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":67580,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V and P-V characteristics of a-Si:H/ µc-Si:H Tandem Solar cell.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/ca92fdbb1c83297ec95b5612.png"},{"id":29144182,"identity":"cc25a541-9a7a-404b-afc8-2b1c9db3f788","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":61428,"visible":true,"origin":"","legend":"\u003cp\u003eNormalized transmission from surface of cell as a function of wavelength.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/0bed68b2a3666b0ae711211f.png"},{"id":29144181,"identity":"b9e43f95-d7c3-4d25-8d6c-210cdab6e311","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":99320,"visible":true,"origin":"","legend":"\u003cp\u003eThe schematic structure of a-Si:H/ µc-Si:H tandem solar cell with proposed ARC.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/fabe200e91b42424b902bd20.png"},{"id":29144195,"identity":"1c13b8c7-ab60-4335-9a0a-be7799b4b7d3","added_by":"auto","created_at":"2022-11-16 15:54:52","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":67596,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V and P-V characteristics of a-Si:H/ µc-Si:H tandem solar cell with proposed ARC.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/c9da1a4a82951b11e614efce.png"},{"id":29144189,"identity":"4bf79cec-3425-43df-b0bb-4e7dcb35b0ff","added_by":"auto","created_at":"2022-11-16 15:54:51","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":53267,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic structure of the proposed DBR.\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/a936ba3aa586c54d951b4592.png"},{"id":29144231,"identity":"ee5c36d5-6297-4256-9fb5-72c8ec4ec5c9","added_by":"auto","created_at":"2022-11-16 15:54:55","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":121776,"visible":true,"origin":"","legend":"\u003cp\u003eNormalized Reflection of the proposed DBR as a function of wavelength.\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/1f07fb6b8c7adaad30421db7.png"},{"id":29144969,"identity":"dd7b2e98-fe0f-4c9e-bf7d-4d6397176d02","added_by":"auto","created_at":"2022-11-16 16:02:53","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":41555,"visible":true,"origin":"","legend":"\u003cp\u003eEfficiency for various numbers of Pair of DBR.\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/8aefc01e27d2fd91c5fac921.png"},{"id":29144220,"identity":"8fa8aa9b-debc-4148-b16d-f2708be0d54b","added_by":"auto","created_at":"2022-11-16 15:54:53","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":118340,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic structure of a-Si:H/ µc-Si:H Tandem Solar cell with proposed DBR.\u003c/p\u003e","description":"","filename":"16.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/194090659c264d0676d73ecb.png"},{"id":29144187,"identity":"dba2a3d1-30bd-4c11-acb3-95cdddeea4b8","added_by":"auto","created_at":"2022-11-16 15:54:51","extension":"png","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":64986,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V and P-V characteristics of a-Si:H/ µc-Si:H Tandem Solar cell with proposed DBR.\u003c/p\u003e","description":"","filename":"17.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/cd4d96764970829800bf6ab3.png"},{"id":29144238,"identity":"cc48a75c-7303-4af9-acfe-a891f0bf9895","added_by":"auto","created_at":"2022-11-16 15:54:55","extension":"png","order_by":18,"title":"Figure 18","display":"","copyAsset":false,"role":"figure","size":97840,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic structure of proposed a-Si:H/ µc-Si:H tandem solar cell.\u003c/p\u003e","description":"","filename":"18.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/f847b66395295e1672d7a49b.png"},{"id":29144193,"identity":"421cf202-bfa3-4957-b3a5-000f45e1a043","added_by":"auto","created_at":"2022-11-16 15:54:52","extension":"png","order_by":19,"title":"Figure 19","display":"","copyAsset":false,"role":"figure","size":64786,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V and P-V characteristics of proposed a-Si:H/ µc-Si:H tandem solar cell.\u003c/p\u003e","description":"","filename":"19.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/e3ec549e53b4ad6209c2c0ac.png"},{"id":29144177,"identity":"5ebdd181-bc9e-41c8-88f6-d756b3e08944","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":20,"title":"Figure 20","display":"","copyAsset":false,"role":"figure","size":205286,"visible":true,"origin":"","legend":"\u003cp\u003eQuantum efficiency for various structures of a-Si:H/ µc-Si:H tandem solar cell.\u003c/p\u003e","description":"","filename":"20.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/a604731e44c275c1c1d0d671.png"},{"id":29144178,"identity":"6b787f5c-428d-464d-9f44-13b28ce6e2f9","added_by":"auto","created_at":"2022-11-16 15:54:50","extension":"png","order_by":21,"title":"Figure 21","display":"","copyAsset":false,"role":"figure","size":134721,"visible":true,"origin":"","legend":"\u003cp\u003eJ-V and P-V curves for various structures of a-Si:H/ µc-Si:H tandem solar cell.\u003c/p\u003e","description":"","filename":"21.png","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/f19ce3f5affa1362d1671aa5.png"},{"id":29144992,"identity":"0505e9e7-0170-4a61-8d64-7d0c934a7775","added_by":"auto","created_at":"2022-11-16 16:02:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1914197,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2268259/v1/591a2f73-9561-49d9-a15f-165a5e3aca5e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Novel Light trapping for high efficiency a-Si:H/ μc-Si Micromorph tandem Solar Cells","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eMulti-junction structures in thin-film technology are generally suggested as a practical solution for reducing loss mechanisms and achieving more efficient utilization of the solar spectrum to improve the collection of photogenerated carriers [1]. One of the major loss mechanisms limiting solar cell performance is the thermalization effect [2] which means a significant part of Photon energy is turned into heat due to the difference between photon energy and electronic bandgap, Eg, of the absorber material.\u003c/p\u003e\n\u003cp\u003eThe simplest multi-junction structure is made of two sub cells in which the top cell has a higher band gap in comparison with the bottom cell. Consequently, photons with low energy, h\u0026upsilon; \u0026lt; Eg, which cannot be absorbed in the top layer transmitted to the bottom cell and then absorbed there.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOwning to its nontoxicity, abundance of raw materials, and low-cost manufacturing [3], thin-film solar cell based on hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (\u0026mu;c-Si:H) as absorber layers has attracted more attention. However, a-Si:H solar cell has two major problems that should be addressed. The first one is a short diffusion length of minority carriers in the absorber layer [4]. The second is light-induced degradation due to the Staebler-Wronski effect [5]. Although, implementing thinner absorber layer partly mitigates these issues, it leads to lower efficiency due to lower generated current. \u0026nbsp;Therefore, the thickness of the absorber layer a-Si:H is limited to a few hundred nanometers.\u003c/p\u003e\n\u003cp\u003eIn order to improve the efficiency of the hydrogenated amorphous silicon solar cells, tandem, Micromorph, cells have been manufactured [6]. Micromorph solar cell is the combination of a-Si:H, with a band gap of ~1.8 ev and \u0026mu;c-Si, with a band gap of ~1.1 ev as a top and bottom layers respectively. Theoretically, as the sub cells are connected in series in tandem solar cell, the sub cell which produces less electron-hole pairs restrict the total current of tandem solar cells. There is no doubt that the top cell, a-Si:H, determines the total current density in Micromorph.\u003c/p\u003e\n\u003cp\u003eThe prime target to reach the maximum efficiency in Micromoph solar cell is to enhance the current density which can be achievable by increasing the optical path length of the incident light [7] and enhancing the light absorption in intrinsic layers with given thicknesses. Advanced light management should be used to improve efficiency.\u003c/p\u003e\n\u003cp\u003eSince amorphous Silicon has a high refractive index, a significant part of incident light is reflected from the surface of the cell. The utilization of anti-reflection coating, ARC on the surface of a solar cell can partly recover this problem. In 2011, Experimental studies have been demonstrated that AR/glass/transparent conducting oxide (TCO)/active layers lead to about 3% reduction of the reflectance (over the 350\u0026ndash;1100 nm range) at the air/glass interface. Therefore, the absorption of light in the active layer is enhanced [8]. In [7] simulated and measured results of using ZnO:Al and SnO2:F as an ARC are shown. In [9] novel double-layered antireflection coatings have been experimented.\u003c/p\u003e\n\u003cp\u003eAnother method for enhancing the light absorption is inserting a high-reflectivity material at the backside, as this can deliberately avoid escaping light from the backside of cells and reflect it into the cell. The influence of back reflectors on the Micromorph performance has been widely simulated and measured in [10, 11]. The conventional back reflector is Silver coated with ZnO [12-15]. One-Dimensional Photonic Crystal, 1DPC, as a back reflector used in amorphous and microcrystalline thin film silicon solar cells to increase the absorption [16-18]. A new concept of a modulated one-dimensional photonic-crystal (PC) structure has been introduced by [19] as a back reflector for thin-film solar cells.\u003c/p\u003e\n\u003cp\u003eCarrier accumulation between the n-layer of a-Si:H and p-Layer of \u0026mu;c-Si can lead to the deterioration of the cell performance [18]. To enhance the recombination rate, electron in n-layer of top cell and the hole in p-layer of the bottom cell, a layer with high conductivity as well as transparent should be implemented between top and bottom cells. In [20] ZnO not only acts as a connector but also is a transparent oxide that can easily transfer light to bottom cell. Another suggestion for interlayer is Tunnel recombination junction, TRJ which could reduce the carrier accumulation [1, 21]. Besides, using a three-dimensional photonic crystal (3D-PC) between the top and bottom cells in Micromorph tandem solar cells has been reported [22].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this paper, we will closely study three different parts of tandem solar cell, front side, intermediate layer between sub cells and backside of cells, by light management techniques to enhance light absorption in both top and bottom cells. A high-efficiency Micromorph solar cell will be proposed through these investigations. In comparison to previous simulated works, our proposed configuration is a result of comprehensive research in which each important part of tandem cell separately investigated and optimized. In addition, optical and electrical parameters used for simulation are taken from the valid experimental study [21, 23], so that the same results prove our simulation have been conducted perfectly.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe body of the paper is organized as follows: first, we will discuss numerical models used in the simulation of Micromorph solar cell. And then the simulation studies are performed on two single solar cell, a-Si:H and \u0026mu;c-Si:H, individually. We will introduce our reference structure which is based on experimental previous work. We will follow this section by utilizing different advanced light trapping methods. We suggest our proposed structure with improved efficiency. Finally, we will close the paper in section 3 with the conclusion.\u003c/p\u003e"},{"header":"2 Numerical Models ","content":"\u003cp\u003eIn this work, Shockley-Read-Hall recombination as a physical model is used to describe the recombination mechanisms in both (p-i-n) a-Si:H and (p-i-n) \u0026micro;c-Si:H cells while for interlayer TRJ, trap-assisted tunneling recombination model could be well-defined. The physical model used for mobility is concentration-dependent low-field mobility model. Disordered Hydrogen and silicon atoms and its amorphous nature introduce many defect states, dangling which is modeled by the Defect Pool Model [21]. For this simulation, the indices of refraction are modeled as having a dependence on wavelength. The tandem solar cell operates under the global standard spectrum, AM 1.5 at a temperature of 300K.\u0026nbsp;\u003c/p\u003e"},{"header":"3\tSimulations and Results ","content":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003e3.1. Single a-Si:H Solar cell\u0026nbsp;\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs it is shown in Fig.1, in the first step single amorphous silicon solar cell consists of ZnO/p-a-Si:H(13 nm)/i-a-Si:H(220 nm)/n-a-Si:H(20 nm)/ZnO/Silver/Al [21] is simulated. Electrical parameters used in the simulation are given in Table.1 and Defect details values are taken from the literature [21]. Here, the intrinsic layer located between p-doped and n-doped layers acts as an absorber layer. For front electrical contact, ZnO is chosen while ZnO/Ag/Al layer is responsible for a back reflector. According to Fig.2 and 3, output parameters obtained from simulation of the cell are as follows: J\u003csub\u003eSC\u003c/sub\u003e=14.32mA/cm\u003csup\u003e2\u003c/sup\u003e, V\u003csub\u003eOC\u003c/sub\u003e=0.9 V, fill factor (FF) =82.15% and conversation efficiency (\u0026eta;) =10.62%. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1. Electrical Parameters of the proposed structure\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"589\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" width=\"21.901528013582343%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLayar \u0026nbsp;properties\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"23.599320882852293%\"\u003e\n \u003cp\u003e\u003cstrong\u003ea-Si:H (top cell)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"22.07130730050934%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026mu;c-Si:H (TRJ)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"7\" width=\"32.42784380305603%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026mu;c-Si:H (bottom cell)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"11.713665943600867%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.327548806941431%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003ei\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.327548806941431%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003en\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.099783080260304%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003en\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.099783080260304%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"14.967462039045554%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"14.533622559652928%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003ei\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"11.93058568329718%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003en\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eThickness (nm)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e220\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"11.186440677966102%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"10.847457627118644%\"\u003e\n \u003cp\u003e2500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eN\u003csub\u003eD\u0026nbsp;\u003c/sub\u003e(cm\u003csup\u003e-3\u003c/sup\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"11.186440677966102%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"10.847457627118644%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eN\u003csub\u003eA\u003c/sub\u003e (cm\u003csup\u003e-3\u003c/sup\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e3\u0026times;10\u003csup\u003e19\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3\u0026times;10\u003csup\u003e19\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"11.186440677966102%\"\u003e\n \u003cp\u003e10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"10.847457627118644%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eE\u003csub\u003eg\u003c/sub\u003e (eV)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eN\u003csub\u003eC\u003c/sub\u003e (cm\u003csup\u003e-3\u003c/sup\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003eN\u003csub\u003eV\u003c/sub\u003e (cm\u003csup\u003e-3\u003c/sup\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e10\u003csup\u003e21\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e3.5\u0026times;10\u003csup\u003e20\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003ec\u0026nbsp;\u003c/span\u003e\u003cspan dir=\"LTR\"\u003e(eV)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e3.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e3.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e3.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e4.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003ee\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp dir=\"RTL\"\u003e\u003cspan dir=\"LTR\"\u003em\u003c/span\u003e\u003csub\u003e\u003cspan dir=\"LTR\"\u003ee\u003c/span\u003e\u003c/sub\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003cspan dir=\"LTR\"\u003e(cm\u003csup\u003e2\u003c/sup\u003e/V\u003csub\u003es\u003c/sub\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.864406779661017%\"\u003e\n \u003cp\u003em\u003csub\u003eh\u003c/sub\u003e (cm\u003csup\u003e2\u003c/sup\u003e/Vs)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.152542372881356%\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.288135593220339%\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"11.016949152542374%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"9.830508474576272%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.5084745762711864%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003e3.2. Single \u0026mu;c-Si:H Solar cell \u0026nbsp;\u003c/strong\u003e\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHere, the single configuration of \u0026mu;c-Si:H solar cell is exactly the same as Single a-Si:H, although, the former has a thicker intrinsic layer, Fig. 4. The thickness of each layer in this structure are p-\u0026micro;c-Si:H (20 nm) / i-\u0026micro;c-Si:H (2500 nm)/ n-\u0026micro;c-Si:H (15 nm) that are adopted from the literature [21].\u003c/p\u003e\n\u003cp\u003eElectrical parameters are taken from the simulation are J\u003csub\u003eSC\u003c/sub\u003e=20.1mA/cm\u003csup\u003e2\u003c/sup\u003e, V\u003csub\u003eOC\u003c/sub\u003e=0.4V, fill factor (FF) =66.97% and conversation efficiency (\u0026eta;) =5.31%. J-V curves and Quantum Efficiency are shown in Fig. 5 and Fig. 6 respectively.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003e3.3. a-Si:H/ \u0026micro;c-Si:H Tandem Solar cell\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn this section, we have proposed a reference structure of Micromoph Solar cell which is depicted in Fig.7. At the front side, ZnO as a transparent conductive oxide with thickness of 40 nm is used while the combination of ZnO (40 nm)/Ag (100 nm)/Al (200 nm) acts as a Back Reflector in the back side of solar cell.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo improve the recombination of the carrier between sub cells, Tunnel Recombination Junction, TRJ, which includes the simple n-\u0026mu;c-Si:H and p-\u0026mu;c-Si:H is suggested. In fact, by tunneling mechanism, holes generated in the bottom cell can be recombined with electrons generated in the top cell in the interface of TRJ due to localized trap states in this area.\u003c/p\u003e\n\u003cp\u003eHere, in order to find optimum TRJ thicknesses, the electrical behavior of solar cell by altering the thickness of TRJ layer has been studied. As simulated Efficiency is shown Fig. 8, by decreasing the thickness of TRJ layer, both layers, the total current density of structure is increased due to high recombination rate in the interlayer. It is obvious by enhancing the current density; efficiency is improved to 12.22%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBased on the simulation demonstrated in Fig. 8, thicknesses TRJ of both n-\u0026mu;c-Si:H and p-\u0026mu;c-Si:H are chosen by 5 nm. As a result, electrical parameters of solar cell will be J\u003csub\u003eSC\u003c/sub\u003e=11mA/cm\u003csup\u003e2\u003c/sup\u003e, V\u003csub\u003eOC\u003c/sub\u003e=1.35V, fill factor (FF) =81.92% and conversation efficiency (\u0026eta;) =12.22%. Fig 9 shows Electrical results of solar cell.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003e3.4. Reference Solar cell with proposed Anti-Reflector\u003c/strong\u003e\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAs mentioned, for lowering the reflection of light from the surface of solar cell, Anti reflector on front side of the cell is normally utilized.\u003c/p\u003e\n\u003cp\u003eSince the used solar spectrum for single-junction solar cells is relatively small, for example, 300-700 nm for a-Si:H solar cells, a single-layer anti reflector like SiO\u003csub\u003e2\u003c/sub\u003e with the thickness of a quarter wavelength is acceptable. However, Multi-junction solar cells such as Micromorph require ARC which is able to transfer most parts of the wide solar spectrum.\u003c/p\u003e\n\u003cp\u003eHere, we introduce a two-layer ARC which is composed of SiO\u003csub\u003e2\u003c/sub\u003e, Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u0026nbsp;\u003c/sub\u003elayers with thicknesses of 230 nm and 55 nm respectively. As it is shown in Fig. 10, more than 90% of light could transfer into the Micromorph through proposed Anti-Reflection coating in wavelength 300-1000 nm. The Micromoph with ARC is demonstrated in Fig. 11.\u003c/p\u003e\n\u003cp\u003eAs it is expected, by adding ARC on the surface of Micromorph, absorption of light increased which causes improvement in J\u003csub\u003eSC\u003c/sub\u003e. While open Circuit Voltage remains nearly unchanged, short circuit current reaches 12.093 mA/ cm\u003csup\u003e2\u003c/sup\u003e from 11 mA/ cm\u003csup\u003e2\u003c/sup\u003e and so efficiency increases to 13.29%. Fig. 12 shows the J-V and PV characteristics of Micromorph with ARC.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003e3.5. a-Si:H/ \u0026micro;c-Si:H Tandem Solar cell with proposed DBR\u003c/strong\u003e\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA significant part of the incident light, mostly in the Infrared region, is not able to be absorbed in the intrinsic layer of a-Si:H due to thin thickness and partly absorbed in \u0026micro;c-Si:H bottom cell. A conventional light-trapping method is Silver coated with Zno, ZnO/Ag coating as back reflector basically suffers from intrinsic losses from surface plasmon modes generated at the metal-dielectric interface [13-15]. The photonic crystals could ideally reflect near 100 % light over a specific wavelength band [18].\u003c/p\u003e\n\u003cp\u003eHere, the combination of Ag/AL is replaced with 1D- photonic crystal, known as Distributed Bragg Reflector, DBR. 1D- photonic crystal is the structure with two different materials with different thicknesses (d\u003csub\u003e1\u003c/sub\u003e, d\u003csub\u003e2\u003c/sub\u003e) and refractive indices (n1, n2) are stacked periodically in one fixed direction. By selecting appropriate materials with larger n1/n2 ratio, the higher reflectance around central wavelength (\u0026lambda;\u003csub\u003e\u0026Beta;\u003c/sub\u003e) will be achieved. In addition, it is required that reflectance bandwidth, known forbidden gap in PC, should be wide, as this can reflect back entire light in solar spectrum into the cell.\u003c/p\u003e\n\u003cp\u003eIn order to achieve maximum reflectance in the range of 700-1200 nm for Micromorph solar cell, Si (n\u003csub\u003e1\u003c/sub\u003e=3.36 at \u0026lambda;=600 nm) and SiO\u003csub\u003e2\u003c/sub\u003e (n\u003csub\u003e2\u003c/sub\u003e=1.48 at \u0026lambda;=600 nm) are chosen. Silicon thickness is calculated 47 nm in the central wavelength, \u0026lambda;\u003csub\u003e\u0026Beta;\u003c/sub\u003e, based on PC formula below:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"858\" height=\"72\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eAfter optimizing the DBR structure, four pair of layers Si/SiO\u003csub\u003e2\u003c/sub\u003e with thicknesses of d\u003csub\u003e1\u003c/sub\u003e, =57nm and d\u003csub\u003e2\u003c/sub\u003e=138 nm, has been suggested, Fig. 13.\u003c/p\u003e\n\u003cp\u003eAs it is depicted in Fig. 14, by rising the number of pairs, more than 95% of light can be reflected in wavelength 600-1200nm. In this way, the distance that light should travel will increase. As a result, by using light trapping, a considerable part of light has been absorbed by solar cell, particularly in the bottom sub cell. Although, one pair DBR has a broader wavelength, normalized reflectance is less than 60%. Moreover, in designing DBR as a back reflector, the main goal is to increase the absorption in long wavelength around 1200nm which four pairs can meet this target.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFig. 15 demonstrates the efficiency of Micromorph solar cell by using different pairs of DBR. As it is expected, when one pair of PC is utilized, efficiency will be 10.29, while the calculated parameter is around 13.68% when a four-pair layer is inserted in the back of solar cell, Fig. 16. Current density and power density characteristics of a-Si:H/ \u0026micro;c-Si:H Tandem Solar cell with proposed DBR is shown in Fig. 17.\u003c/p\u003e\n\u003cp\u003eIn comparison of Zno/Ag/Al as a Back Reflector, Zno/DBR increases the current density 12.27 mA/cm\u003csup\u003e2\u003c/sup\u003e while V\u003csub\u003eOC\u003c/sub\u003e and Fill Factor (FF) will be 1.36 and 82.15%, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003e3.6. Modification of Doping in Proposed Micromorph \u0026nbsp;\u003c/strong\u003e\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this part, by incorporating all TRJ, SiO\u003csub\u003e2\u003c/sub\u003e/Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u0026nbsp;\u003c/sub\u003eand 1DPC in the Micromorph solar cell, the efficiency of the final configuration improved. \u0026nbsp;Fig. 18 shows the proposed a-Si:H/ \u0026micro;c-Si:H tandem solar cell. According to the simulation, efficacy of the final solar cell reaches 13.71% after performing advanced light trapping.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBy adding uniform impurity concentration to p-a-Si:H and n layer of TRJ could gain 14% of conversion efficiency. \u0026nbsp;The impurity of p-a-Si:H and n layer of TRJ have been selected 4\u0026times;10\u003csup\u003e20\u003c/sup\u003e cm\u003csup\u003e-3\u0026nbsp;\u003c/sup\u003eand 2\u0026times;10\u003csup\u003e20\u003c/sup\u003e cm\u003csup\u003e-3\u0026nbsp;\u003c/sup\u003erespectively. The simulated values for the electrical characteristics are J\u003csub\u003eSC\u003c/sub\u003e=12.51mA/cm\u003csup\u003e2\u003c/sup\u003e, V\u003csub\u003eOC\u003c/sub\u003e=1.38 V, FF=80.82% and\u0026nbsp;𝜂=14%. J-V and P-V characteristics of proposed a-Si:H/ \u0026micro;c-Si:H tandem solar cell is shown in Fig. 19.\u003c/p\u003e\n\u003cp\u003eFigs. 20 and 21 compare the electrical and optical characteristics of the Micromorph solar cell for various structures added to cell, separately. As these figures show, there is a considerable improvement in quantum efficiency especially in the bottom cell; this enhancement is clearly depicted in J-V as well as P-V curves. Utilizing advanced light management shows that current density improved while open circuit voltage stayed certain.\u003c/p\u003e\n\u003cp\u003eTable 2 shows a comparison of the proposed structure with works reported in the past few years. As one can see the result of simulation of the proposed structure is acceptable and nearly to close to experimental results.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Electrical Parameters of the proposed structure\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"438\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003e\u003cstrong\u003eWork\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e\u003cstrong\u003eJ\u003csub\u003eSC\u003c/sub\u003e(\u003c/strong\u003e\u003cstrong\u003emA/cm\u003csup\u003e2\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e\u003cstrong\u003eV\u003csub\u003eOC\u003c/sub\u003e (v)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e\u003cstrong\u003eFF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e\u003cstrong\u003eEff\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eRef [23]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e13.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.342\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e70.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e12.29-13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eRef [3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e13.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.391\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e71.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e13.65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eRef [24]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e10.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e69.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e10.655\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eRef [25]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e12.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e11.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eRef [26]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e11.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e67.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.14611872146119%\"\u003e\n \u003cp\u003eThis Work\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.570776255707763%\"\u003e\n \u003cp\u003e12.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.296803652968036%\"\u003e\n \u003cp\u003e1.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.319634703196346%\"\u003e\n \u003cp\u003e80.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"4\tConclusion ","content":"\u003cp\u003eIn this paper, we have conducted three methods to develop photon absorption in top and bottom cells of Micromorph solar cell. TRJ is an effective way to improve recombination rate in interface of sub cells. Anti-reflection coating utilized on the top cell causes that current density about 9% increases. \u0026nbsp;As a result, conversion Efficient reaches 13.29%. Moreover, by incorporating DBR in the backside of Micromorph, current 12.27 mA/cm\u003csup\u003e2\u003c/sup\u003e increases.\u003c/p\u003e\n\u003cp\u003eDoping modification and applying all of mentioned proposed light trapping methods in Micromorph solar cell shows a significant improvement compared to reference cell. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.38 V, a short-circuit current density of 12.51 mA/cm\u003csup\u003e2\u003c/sup\u003e, and a fill factor of 80.82%, corresponding to a total area conversion efficiency of 14%.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding statement\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis paper is not financially supported by any organizations and institutions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that there is no conflict of interest reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll the works in this paper (study conception and design, material preparation, data collection and analysis) have done together by\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003eRamisa Eghbali, Saeed Khosroabadi and Anis Shokouhmand. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors voluntarily agree to participate in this research study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have endorsed the publication of this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data and material are available within the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003e Madaka, R., Kumar, D., Singh, A. 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Material study on ZnO/Ag back reflectors for silicon thin film solar cells. 23rd EU PVSEC Proc, 3: 2419-2421.\u003c/li\u003e\n \u003cli\u003e M\u0026uuml;ller, J., Rech, B., Springer, J., \u0026amp; Vanecek, M. (2004). TCO and light trapping in silicon thin film solar cells. Sol Energy, 77: 917-930.\u003c/li\u003e\n \u003cli\u003e Springer, J., Poruba, A., M\u0026uuml;llerova, L., Vanecek, M., Kluth, O., \u0026amp; Rech, B. (2004). Absorption loss at nanorough silver back reflector of thin-film silicon solar cells. J Appl Phys, 95: 1427-1429.\u003c/li\u003e\n \u003cli\u003e Paetzold, U. W., Hallermann, F., Pieters, B. E., Rau, U., Carius, R., \u0026amp; Von Plessen, G. (2010, May). Localized plasmonic losses at metal back contacts of thin-film silicon solar cells. In Photonics for Solar Energy Systems III (Vol. 7725, p. 772517). International Society for Optics and Photonics.\u003c/li\u003e\n \u003cli\u003e Biswas, R., \u0026amp; Zhou, D. (2007). 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N., Tobbeche, S., \u0026amp; Merazga, A. (2017). Influence of \u0026mu;c-Si: H tunnel recombination junction on the performance of a-Si: H/\u0026mu;c-Si: H tandem solar cell. Optik, 139: 152-165.\u003c/li\u003e\n \u003cli\u003e Bielawny, A., \u0026Uuml;pping, J., Miclea, P. T., Wehrspohn, R. B., Rockstuhl, C., Lederer, F., ... \u0026amp; Carius, R. (2008). 3D photonic crystal intermediate reflector for micromorph thin‐film tandem solar cell. Phys Status Solidi a, 205: 2796-2810.\u003c/li\u003e\n \u003cli\u003e Matsui, T., Bidiville, A., Maejima, K., Sai, H., Koida, T., Suezaki, T., ... \u0026amp; Kondo, M. (2015). High-efficiency amorphous silicon solar cells: Impact of deposition rate on metastability. Appl Phys Lett, 106: 053901.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e Liu, D., Wang, Q., \u0026amp; Wang, Q. (2018). Transfer the multiscale texture of crystalline Si onto thin-film micromorph cell by UV nanoimprint for light trapping. Appl Surf Sci, 439: 168-175.\u003c/li\u003e\n \u003cli\u003e Das, G., Bose, S., Mukhopadhyay, S., Banerjee, C., \u0026amp; Barua, A. K. (2019). Innovative utilization of improved n-doped \u0026mu;c-SiOx: H films to amplify the performance of micromorph solar cells. Silicon, 11: 487-493.\u003c/li\u003e\n \u003cli\u003e Li, W., Tang, L., Du, J., Xue, F., Luo, Z., \u0026amp; Liu, S. (2019). Hydrogen annealed ZnO: B film grown by LPCVD technique as TCO for enhancing conversion efficiency of a-Si: H/\u0026mu;c-Si: H tandem solar cells. Sol Energy Mater Sol Cells, 200: 109942.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Micromorph Solar cell, Tunnel Recombination, Junction, Light trapping, a-Si:H","lastPublishedDoi":"10.21203/rs.3.rs-2268259/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2268259/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe performance of a-Si:H/μc-Si:H tandem solar cell has been studied by using two-dimensional numerical simulation. In this work, after optimizing the thicknesses of each layer, light trapping techniques have been investigated to increase the photogenerated current in both sub cells. 1D- photonic crystal has been implemented as a broadband back reflector in a solar cell while to reduce the reflection from the surface of the top cell, two-layer anti-reflection, SiO\u003csub\u003e2\u003c/sub\u003e/Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e has been suggested. In order to match the current density of sub cells as well as prevent the accumulation of carries in its interface, Tunnel Recombination Junction is required in the interlayer. Here, we have used n-μc-Si:H /p-μc-Si:H with a thickness of 10nm as a TRJ. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.38 V, a short-circuit current density of 12.51 mA/cm\u003csup\u003e2\u003c/sup\u003e, and a fill factor of 80.82%, corresponding to a total area conversion efficiency of 14%.\u003c/p\u003e","manuscriptTitle":"A Novel Light trapping for high efficiency a-Si:H/ μc-Si Micromorph tandem Solar Cells","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-11-16 15:53:12","doi":"10.21203/rs.3.rs-2268259/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d438d68b-fe21-4e5d-aeb1-0dab99549ca0","owner":[],"postedDate":"November 16th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-11-16T15:54:29+00:00","versionOfRecord":[],"versionCreatedAt":"2022-11-16 15:53:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2268259","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2268259","identity":"rs-2268259","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}