Design of Resonant Cavity-Enhanced InAs/GaSb Superlattice LWIR Photodetector

Design of Resonant Cavity-Enhanced InAs/GaSb Superlattice LWIR Photodetector | 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 Article Design of Resonant Cavity-Enhanced InAs/GaSb Superlattice LWIR Photodetector Ruixin Gong, Lianqing Zhu, Qingsong Feng, Zhiying Liu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4579072/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 Type-II superlattices (T2SLs) have recently emerged as a focal point in long-wavelength infrared (LWIR) detection, showcasing remarkable potential across various applications. In this work, we have revealed a theoretical investigation into the band structure and optical properties of 14/7 ML InAs/GaSb SLs, employing density functional theory (DFT). Our findings show that the energy gap of these SLs is determined to be 0.111 eV through energy band structure analysis by the HSE06 method. Moreover, we have designed a resonant cavity-enhanced "Φ" structure for the 14/7 ML InAs/GaSb SLs infrared detector. This innovative design markedly enhances absorption efficiency, increasing it from 16.48% to an impressive 76.35% at the 11.2 µm wavelength. Further analysis includes a detailed examination of the electric field distribution within this structure and a comprehensive examination of the enhanced plasmonic resonator's perfect absorption phenomenon. The results from these analyses underscore the exceptional absorption capabilities of our resonant cavity-enhanced infrared detector, indicating its potential for significant applications in LWIR SLs focal plane. Physical sciences/Materials science/Materials for optics/Metamaterials Physical sciences/Mathematics and computing/Computational science Type-II superlattice detectors First principle resonant cavity-enhanced infrared detector long-wavelength infrared Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Infrared detection technology, particularly in the military domain, has undergone significant advancements, propelled by the need for enhanced surveillance, target acquisition, and missile guidance capabilities 1 , 2 . The longwave infrared window, spanning 8 µm to 14 µm, is critical for night vision applications due to its ability to detect thermal radiation emitted by various objects 3 . The discovery of HgCdTe by Lawson et al. in 1959 marked an initial breakthrough in infrared detection. However, issues with the inhomogeneity of its ion-bonded semiconductor alloys, especially in long-wavelength detection, led to decreased detector performance 4 . This challenge was addressed in 1977 by Sai-Halasz et al. with the introduction of Type II InAs/GaSb superlattices (SLs) 5 . Notably, SLs are noted for their tunable bandgap, uniform growth, high absorption coefficient, and efficiency, showing promise in surpassing HgCdTe in long-wave infrared detection within the 8 µm -14 µm range. 6 . Advancements in infrared detectors have been marked by improved methods for assessing the electronic structure and optical properties of materials. Techniques like the envelope function approximation of the K.P. method, the semi-empirical tight-binding approximation, and the pseudopotential plane wave approximation have been notable 7 . However, these conventional methods haven't fully addressed issues related to point defects and interfaces. First-principles calculations offer more precise computation of the electronic structure and optical properties of InAs/GaSb SLs, presenting a new direction for energy band structure optimization 8 . Furthermore, as device sizes decrease, surface leakage currents, a major contributor to dark current in large-area focal plane arrays, become a significant concern 3 . This study focuses on optimizing infrared radiation propagation using a hypersurface structure. Incorporating a resonant cavity on the InAs/GaSb SLs detector's surface generates a localized surface plasmon resonance effect 9 , enhancing the coupling of optical radiative energy to the metal surface and directing incident light into an in-plane propagation pattern 10 . Our research delves into the band structure and optical properties of 14/7 monolayers (ML) InAs/GaSb SLs using first-principles computational methods. These findings are crucial in developing a novel resonant cavity-enhanced "Φ" structure for infrared detectors. The study includes a detailed analysis of material simulation, electronic and optical properties, and the application of metasurface resonant cavity in long-wavelength infrared detectors. We establish the 14/7 ML InAs/GaSb SLs structure and investigate its charge density distribution and chemical bond characteristics. The electronic band structure and density of states are calculated for bulk InAs, bulk GaSb, and the 14/7 ML InAs/GaSb SLs using PBE and HSE06 first-principles methods. Optical properties such as reflectance, refractive index, absorption spectrum, and extinction coefficient are primarily determined through the real and imaginary parts of the dielectric function. A key aspect of our study is designing and analyzing a "Φ" structure 14/7 ML InAs/GaSb SLs infrared detector. This design significantly increases absorption efficiency in the LWIR spectrum, notably at 11.2 µm, from 16.48–99.95%. The phenomenon of enhanced plasmonic resonator perfect absorption in the LWIR SLs is thoroughly analyzed, including detailed electric field distribution within the LWIR photodetector structure. The annular resonators in the "Φ" structure induce localized mode-splitting resonance at 11.2 µm, enhancing light absorption. This resonant cavity-enhanced infrared detector demonstrates strong absorption capabilities in the infrared region, suggesting potential applications in long-wavelength SLs focal plane imaging. 2. Computational Method The present research employed the density-functional theory (DFT) from the Vienna ab initio Simulation Package (VASP) for conducting rigorous first-principal calculations 11 . The interactions between ions and valence electrons were analyzed using the projector augmented wave (PAW) method 11 , 12 , and the Perdew-Burke-Ernzerhof (PBE) functional was employed for these calculations 13 . The band structures and density of states, taking into account the spin-polarized effects of electrons, were calculated using the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functionals 14 , 15 . A plane wave energy cutoff of 400 eV was set, and convergence criteria for atomic force and energy were established at 0.02 eV and 1×10 − 5 eV/Å, respectively. Geometric optimization and band structure calculations were conducted using a 4×4×4 k -point mesh for bulk materials, and 2×2×1 k -point mesh for supercell 14/7 ML InAs/GaSb SLs. The objective of this study is to explore long-wave hypersurface infrared detectors using Type II InAs/GaSb superlattice (SL) materials. We introduced a hypersurface structure that enhances surface plasmon resonance, aimed at increasing absorptivity in the long-wave range. DFT simulations were performed on Type II SL materials to analyze the optical and electrical properties of a periodic InAs/GaSb SL comprising 14 atomic layers of InAs and 7 atomic layers of GaSb. The calculations were conducted with gallium (Ga) as the reference point and indium antimonide (InSb) as the interface layer. Additionally, a metallic hypersurface "Φ" structure was simulated atop the device, with specific dimensions and orientation as illustrated in Fig. 1 (a). The device structure included a bottom reflective layer made of 100 nm-thick gold (Au), and the absorber layer was composed of a long-wavelength 14/7 ML InAs/GaSb SL, with a periodic thickness of 6.137 nm. A periodic array of "Φ" structures was designed with an outer diameter of 900 nm, inner diameter of 410 nm, rectangular structure length ( \({l}_{1}\) ) of 1900 nm, rectangular structure width ( \({l}_{2}\) ) of 200 nm, and a counterclockwise 60° angle, as indicated by Fig. 1 (b). Moreover, the simulation of the infrared detector device is illustrated in Fig. 1 (c). The device was constructed with a total of 410 cycles, resulting in an overall thickness of approximately 2500 nm, aligning with standard expectations for SLs thickness. Notably, a thin adhesive layer is usually applied between the Au layer and the SLs absorber layer to enhance ohmic contact and prevent metal diffusion. However, experimental calculations revealed that the optical loss of the adhesion layer was found to be extremely negligible. The model was simplified by setting each unit structure to a size of 2000 nm × 2000 nm, arranged periodically along the x and y axes to form a periodic array, is illustrated in Fig. 1 (d). The "Φ" structure was instrumental in developing an InAs/GaSb infrared detector with precise optical and electrical properties in the LWIR SLs absorption region, further enhanced through surface plasmon resonance, as illustrated in Fig. 1 (e). For accurate simulation of the optical properties of gold in the metal "Φ" structures and metal reflectors, the wavelength-domain wave optics module of COMSOL software was utilized. The variation in the dielectric constant of gold with wavelength, as detailed in literature 16 , was referenced for this purpose. In the simulation setup, the detector was illuminated with light perpendicular to the x-y plane along the z-axis, allowing for the measurement of reflectance, absorptance, and transmittance, adhering to the equation R + A + T = 1 10 . To accurately represent the periodic system, periodic port and periodic boundary conditions were implemented along the x and y axes, ensuring that the propagation of light in the simulation accurately reflected the periodic structure of the system. 3. Simulation Results and Analysis A. Electronic Properties of 14/7 ML InAs/GaSb SLs Charge density refers to the spatial distribution of electrons, and it has a significant impact on the geometric arrangement and chemical bonding properties of InAs, GaSb, and InSb. By analyzing charge density, we can infer the atomic arrangement of indium (In), arsenic (As), gallium (Ga), and antimony (Sb) on various crystallographic planes. Furthermore, the charge density helps elucidates the nature of chemical bonds, such as ionic or covalent bonds between atoms. For instance, consider the (110) plane as depicted in Fig. 2 (a). This plane comprises a 7-atom layer of GaSb and a 14-atom layer of InAs, both forming a sphalerite structure characterized by the space group F-43 m 17 . Within the GaSb layer, each gallium atom is tetrahedrally coordinated to four antimony atoms, and vice versa. The charge density distribution on the (110) plane, depicted in Fig. 2 (b), reveals a notable variation in Ga-Sb bond lengths. Initially, the bond length is 2.66 Å, but it extends to 5.088 Å in the subsequent layers 7 . This variation is attributed to the lattice constant mismatch, with InAs having a lattice constant of 6.107 Å and GaSb, 6.137 Å, resulting in tensile strain at the GaSb interface. The electron distribution in this map indicates a difference in geometric configuration, particularly at the InAs and GaSb interface where electron clouds are more concentrated around In and Ga atoms, suggesting stronger In-As bonds compared to the weaker Ga-Sb covalent bonds. Figures 2 (c) and (d) display the SLs charge density distribution on the (001) and (011) planes, respectively. The (001) plane predominantly features weak covalent bonds within InAs, characterized by shared electron pairs between InAs atoms, leading to a uniform charge distribution. The outer electron clouds on these facets are incompletely filled, indicative of a weak covalent bonding state. In contrast, the (011) plane, as shown in Fig. 2 (d), likely has a denser atomic arrangement due to bonding between surface and internal atoms. The elevated surface energy on this plane causes a more compact charge distribution, thereby increasing the charge density. Figures 3 (a) and (b) display the electronic band structure and density of states for bulk InAs material, bulk GaSb material, and the 14/7 ML InAs/GaSb SLs. These results were obtained by comparing the PBE and HSE06 computational methods. The analysis focuses on the X-Gamma-X path in the first Brillouin zone, with a direct band gap observed at the Gamma point. Notably, the energy band structures are depicted relative to the atomic sizes of the constituent elements. At the Gamma point, the band gap (Eg) represents the energy difference between the valence band's highest energy level (VB) and the lowest energy level in the conduction band (CB). The density of states offers insights into electron distribution across energy levels. Figures 3 (a) and (b) contrast the band gap energies in zinc blende bulk InAs, while Figs. 3 (c) and (d) contrast the band gap energies in s zinc blende bulk GaSb, all calculated using PBE and HSE06 methods. PBE calculations suggest negligible band gaps for both InAs and GaSb 13 . The conduction band energies of InAs are influenced by group V elements, whereas in GaSb, the conduction band is predominantly governed by gallium (Ga), and the valence band by antimony (Sb). The discrepancy in the PBE method is linked to its exchange-correlation energy approximation, which leads to deviations in band gap estimations. For instance, in GaSb and InAs/GaSb SLs, the PBE method inaccurately interchanges the positions of the conduction band top and the valence band bottom, as shown in Fig. 3 (e). To address the issue of ionization energy shifts common in DFT methods, a novel approach for 14/7 ML InAs/GaSb SLs has been developed, incorporating long-range corrections. The HSE06 method, known for its precision in simulating conduction and valence band behavior in semiconductors, is employed in these calculations. As illustrated in Fig. 3 (b), the energy band structure of InAs shows an energy gap of 0.366 eV, aligning well with existing literature findings 18 . The InAs conduction band is influenced by both indium (In) and arsenic (As), while the valence band is primarily determined by As. In contrast, Fig. 3 (d) shows that GaSb, despite its zinc blende structure and semiconductor nature, exhibits an energy gap of 0.772 eV, with only slight deviations from previously reported results 19 . In GaSb, the conduction band is largely influenced by Ga, with the valence band being affected by both Sb and Ga, though Sb plays a more prominent role. Additionally, Fig. 3 (f) demonstrates that the band structure of the 14/7 ML InAs/GaSb SLs is primarily dictated by Ga and Sb, exhibiting an energy gap of 0.111 eV. This result aligns with calculations using the conventional Kane-Penning (KP) model and falls within the long-wave absorption region's range 20 . B. Optical Properties of 14/7 ML InAs/GaSb SLs The energy-dependent optical properties of bulk InAs and GaSb materials, as well as 14/7 ML InAs/GaSb SLs. The dielectric function is analyzed in terms of its real and imaginary parts, while reflectivity, refractive index, absorption spectra, and extinction coefficient are also examined by the HSE06 method. Figures 4 (a) and (b) present the real and imaginary parts of the dielectric constants for bulk InAs, bulk GaSb, and 14/7 ML InAs/GaSb SLs. The real part indicates the material's absorption properties of electromagnetic waves, while the imaginary part reflects the material's ability to dissipate energy in the presence of an electric field 21 , 22 . As shown in Fig. 4 (a), both InAs and GaSb bulk materials exhibit absorption capabilities in the energy range of 0.5-1.0 eV and 2.0-2.5 eV, respectively. However, the 14/7 ML InAs/GaSb superlattices (SLs) exhibit strong absorption of electromagnetic waves with energies below 0.5 eV and demonstrate effective accumulation of charge or polarization. However, the absorption capability of 14/7 ML InAs/GaSb SLs exhibits an exponential decline beyond 0.5 eV, resulting in reduced dielectric loss. This distinctive characteristic significantly diminishes energy loss and signal attenuation, emphasizing the exceptional attributes of these SLs 23 – 25 . Figure 4 (b) demonstrates that bulk InAs has strong electric field absorption ability but poor electromagnetic wave transmission ability. The 14/7 ML InAs/GaSb SLs, however, exhibit intermediate properties between the two bulk materials, maintaining strong absorption ability while facilitating better transmission of electric field energy 26 , 27 . Figures 4 (c) and (d) display the reflectance and refractive index characteristics of bulk InAs and GaSb, as well as 14/7 ML InAs/GaSb superlattices (SLs). The figures demonstrate that all three materials exhibit a significantly high reflectivity. Among them, the 14/7 ML InAs/GaSb SLs demonstrate a minimum reflectivity of 40%. This finding strongly implies that the superlattice has a pronounced capability for reflecting incident light, while its light absorption potential is limited 27 . Furthermore, Fig. 4 (d) demonstrates that the refractive indices of bulk InAs and GaSb remain low and constant, whereas the refractive indices of the 14/7 ML InAs/GaSb SLs measure below 0.5 eV, resulting in slower light propagation and higher optical loss. Inspection of the absorption spectra in Fig. 4 (e) reveals the first absorption peaks at 0.417 eV for GaSb and 0.235 eV for InAs materials. These peaks correspond to the energy gap between the highest occupied energy band and the lowest unoccupied energy band, indicative of specific electron transitions, supporting the findings of previous studies. Notably, the absorption peak of the 14/7 ML InAs/GaSb SLs aligns closely with 0.1107 eV, approximately corresponding to the long-wavelength 11.2 µm 28 . The presented figure provides visual evidence of the wide spectral response displayed by the superlattice, which aligns with its prominent response peak in the longer wavelength range of 8 µm to 14 µm. Furthermore, it is evident from Fig. 4 (f) that the 14/7 ML InAs/GaSb superlattice outperforms both bulk InAs and GaSb materials in terms of its remarkable light absorption and scattering capabilities 29 , 30 . C. Enhanced InAs/GaSb SLs Long-wave Infrared Detector Optical properties Figure 5 (a) displays the optical performance of 14/7 ML InAs/GaSb SLs in LWIR SLs detectors, particularly focusing on absorptivity, reflectance, and transmittance within the 8 µm to 14 µm wavelength range 29 . The figure indicates that the dielectric function of these materials is determined using first-principles calculations. Without any metallic reflector or hypersurface structure, the absorptivity at the 11.2 µm wavelength is relatively low, at about 16.48%. Nonetheless, the material demonstrates high reflectance, exceeding 60% in the 10 µm to 11 µm range, and a significant transmittance of up to 95.03%. In contrast, the "Φ" structure metamaterial detector illustrated in Fig. 5 (b) effectively manipulates the absorbance of the SLs material, significantly decreasing both reflectance and transmittance. With this structure, absorptivity can exceed 99.95%, while reflectivity is reduced to less than 1%, attributable to the minimal transmittance of metallic gold (Au) at the 11.2 µm wavelength. As a result, this enhanced SL structure substantially improves the light absorptivity of the T2SLs detector across a broader spectrum of long-wave infrared radiation 31 . Simultaneously, we modified the key parameters of the enhanced hypersurface detector with a specific focus on absorptivity. These parameters encompassed the thickness of the 14/7 ML InAs/GaSb SLs (h_T2SLs), the thickness of the gold layers (h_Au and h_Au_bottom), the radii of the rings (r 1 and r 2 ), and the dimensions and angles of the rectangles on the rings ( \({l}_{1}\) , \({l}_{2}\) , and angle). Absorptivity, especially influenced by the thickness of the SLs material, affects both the absorption wavelength range and intensity 32 . Figure 5 (c) shows that within a thickness range of 200 nm to 1000 nm, a SLs with a thickness of 200 nm achieved an absorptivity of up to 99%, but with a narrower wavelength half-width of 0.7 eV. However, when the SLs material was too thin, the gold layers on the surface predominantly absorbed the light, leading to a decrease in light absorptivity by more than 10% for every 100 nm increase in thickness. Furthermore, Fig. 5 (d) demonstrates that selecting a material thickness in the range of 2300 nm to 3000 nm narrows the wavelength range between 11 µm and 11.5 µm. Increasing the thickness causes a red-shift in the wavelength, with an absorptivity exceeding 99% and a wavelength half-width of around 0.1 eV observed at a thickness of 2500 nm. This finding highlights the crucial impact of SLs thickness on absorptivity, with optimal absorption achieved around a thickness of 2500 nm. Figures 6 (a) and (b) showcase two-dimensional absorption spectroscopy images, providing insights into the enhanced plasmonic structures and SLs materials. These images are instrumental in intuitively optimizing and analyzing how the thickness of SLs materials influences the intensity and wavelength of light absorption. In Fig. 6 (a), it can be observed that within the wavelength range of 9 µm to 11.5 µm, the absorptivity is higher than 70%. The absorption is predominantly concentrated around the 11 µm wavelength, thereby amplifying the effect 33 . Figure 6 (b) indicates that the light absorption intensity of SLs with an enhanced plasmonic structure is mainly significant for thicknesses of 1500 nm and above. It appears that the gold (Au) material, particularly within a thickness of 500 nm, contributes significantly to the absorptivity. However, a single layer of SLs material, at a thickness of 2300 nm or more, achieves an absorptivity of 76.35% at the 11.2 µm wavelength. This level of absorption represents a substantial increase, nearly five times higher, compared to a single 14/7 ML InAs/GaSb SLs. Further details are provided in Figs. 6 (c) and (d), which illustrate the absorption spectra of the enhanced plasmonic structure and SLs across various outer diameters and wavelengths 32 . Figure 6 (c) shows that changes in the outer diameter have a minimal impact on the wavelength. The enhanced plasmonic structure demonstrates peak light absorption when the radius exceeds 600 nm. Conversely, as per Fig. 6 (d), the SLs exhibit a similar absorption pattern but cease to absorb light effectively for a radius exceeding 920 nm. This pattern underlines the influence of structural dimensions on the light absorption capabilities of these materials 34 . Electric field analysis To comprehensively understand the perfect absorption phenomenon induced in LWIR SLs using an enhanced plasma resonator, it is essential to examine the effect of localized electric field enhancement on the underlying physical mechanism. This understanding can be achieved through a comprehensive analysis of the electric field distribution across the entire LWIR photodetector structure. Figures 7 (a) to (c) display the electric field distribution in the XY plane, while Figs. 7 (d) to (f) present the distribution in the YZ plane. In these illustrations, the planes are positioned at either an X or Z coordinate of 50 nm. The plots utilize red and blue colors to represent the strongest and weakest electric fields. Figures 7 (a) and (d) depict the electric field distribution on the surface and cross-section of the SLs without the resonator and metal reflection layer. In these scenarios, the electric field on the surface is uniformly distributed, but the cross-sectional field is predominantly absorbed at the surface, with minimal penetration into the SLs 9 . Conversely, Figs. 7 (c) and (e) show the electric field at the interface of the ring resonator and the SLs. Here, the electric field is intensely concentrated at the junction of the resonator and the SLs surface, coinciding with the highest field intensity area. This pattern suggests that the surface-iso-excitation resonance confines the incident light's energy primarily within the metallic Au layer 30 . Furthermore, Figs. 7 (c) and (f) demonstrate that in the ring-square resonator, the electric field is mainly focused within the inner region of the SLs material. This configuration not only enhances the field's intensity but also establishes a continuous current flow between the resonator layer and the Au reflecting layer, creating a loop current between these metal layers 35 . This localized enhancement is sustained throughout the 14/7 ML long-wavelength InAs/GaSb SLs depletion layer in the detector. Consequently, the ring-square resonator with a "Φ" structure efficiently excites a localized equipartitioned exciton resonance at a wavelength of 11.2 µm. This result underscores the importance of resonator design in optimizing the photodetection capabilities of the LWIR SLs detectors. 4. Conclusion In conclusion, we have presented a comprehensive analysis of material simulation, electronic and optical properties, and the integration of metasurface resonant cavities in long-wavelength infrared detectors. Employing first-principles computational methods, we examined the band structure and optical characteristics of 14/7 ML InAs/GaSb SLs, which were facilitated the development of a "Φ" structure infrared detector, enhanced by a resonant cavity. We successfully determined the energy gaps of 0.366 eV for InAs and 0.772 eV for GaSb utilizing the HSE06 method. Additionally, the band structure analysis of the 14/7 ML InAs/GaSb SLs further indicated an energy gap of 0.111 eV, effectively placing it within the desired longwave absorption region. Furthermore, we designed a detector that demonstrates exceptional absorption capabilities, achieving absorption efficiency in the LWIR spectrum, notably at 11.2 µm, from 16.48–76.35%. Our research included an in-depth examination of the electric field distribution within the detector structure, as well as an analysis of the phenomena associated with the enhanced plasmonic resonator and its perfect absorption capability. These findings confirm the substantial absorption potential of the resonant cavity-enhanced infrared detector. The results highlight the detector's promising applications in long-wavelength SLs focal plane imaging systems, marking a significant advancement in the field of infrared detection technology. Declarations Author Contributions: R.G. made the basic simulation and wrote the manuscript. Z.L. re-viewed and edited the final draft of the manuscript. X.Z. and Q.F contributed to basic conceptualization. B.L., Y.C., and Y.Z. helped in the theoretical analysis and the interpretation of the results. Y.C., Q.F., and X.Z provided useful advice and assistance. All authors have read and agreed to the published version of the manuscript. Acknowledgments: This work was supported by the Beijing Scholars Program (Grant No. BJXZ20210016), National Natural Science Foundation of China (Grant No.62205029), 111 Project of China (D21009). Conflicts of Interest: The authors declare no conflict of interest. Compliance with ethical standards: All data generated or analysed during this study are included in this published article. The datasets used and analysed during the current study available from the corresponding author on reasonable request. References Razeghi, M. et al. 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All-d-metal equiatomic quaternary Heusler hypothetical alloys ZnCdTMn (T = Fe, Ru, Os, Rh, Ir, Ni, Pd, Pt): A first-principle investigation of electronic structures, magnetism, and possible martensitic transformations. Results in Physics 11, 1134–1141 (2018). Jung, J.-Y. et al. Infrared broadband metasurface absorber for reducing the thermal mass of a microbolometer. Sci Rep 7, 430 (2017). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4579072","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":321432461,"identity":"b84d2d6b-c28b-4789-a916-c19ae60c7c8a","order_by":0,"name":"Ruixin Gong","email":"","orcid":"","institution":"Changchun University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Ruixin","middleName":"","lastName":"Gong","suffix":""},{"id":321432462,"identity":"7a14fd9e-5557-46b1-8a8e-bef7b4f625e1","order_by":1,"name":"Lianqing Zhu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA10lEQVRIie3RPQrCMBTA8VeEdHnoGqnQK0SEbNKrtBTaVXFyE4ROghcQvILeQHjYMwh2KAiZXNw6iBiLiFNaN4f8h2TJj3wB2Gx/WBeA6emAenBKEC0I+xAGHfETeU2MtzoYc1N1QSgG/nYl59Wk8MGl485IsExHCApFjvKMQg0XmCQnI+Fh7iEQCqYJCHIWHGUDibKa+BnKaSUoaEFiVhPQBwMUFDUTVKy/qe+SzDxN4qzpLj39YvwKReAvaX+r7jReu5QbCUCov/3xva95+ZvYbDabzdgT/CY/eDnaWAwAAAAASUVORK5CYII=","orcid":"","institution":"Beijing Information Science and Technology University","correspondingAuthor":true,"prefix":"","firstName":"Lianqing","middleName":"","lastName":"Zhu","suffix":""},{"id":321432463,"identity":"76f97522-fbca-4ddd-b968-88fcdb59f198","order_by":2,"name":"Qingsong Feng","email":"","orcid":"","institution":"Beijing Information Science and Technology University","correspondingAuthor":false,"prefix":"","firstName":"Qingsong","middleName":"","lastName":"Feng","suffix":""},{"id":321432464,"identity":"8c3b5e19-b0a4-4b7c-baa5-6fb5136f0f9f","order_by":3,"name":"Zhiying Liu","email":"","orcid":"","institution":"Changchun University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Zhiying","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2024-06-14 03:05:56","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4579072/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4579072/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":59509300,"identity":"7a6d3f70-bb62-4ad0-be46-c3de91d530f1","added_by":"auto","created_at":"2024-07-02 15:59:10","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":459917,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of the LWIR detector based on the 14/7 multiple layer (ML) InAs/GaSb T2SLs. The LWIR detector configuration is comprised of various components: (a) a perspective view illustrating the periodic array \"Φ\" structure embedded within LWIR materials positioned on an Au substrate, (b) a top-view depiction of the infrared detector metasurface comprising the T2SLs, (c) and (d) side-views indicating the thickness of the different layers, and (e) the surface of the periodic array structure surrounding the irradiation of infrared light.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/0d588520e6a20a919fb7587e.png"},{"id":59509303,"identity":"565420a6-0964-4f2a-8f45-b6242bc64061","added_by":"auto","created_at":"2024-07-02 15:59:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":461498,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The model construction of the single-period model of a 14/7 ML InAs/GaSb SLs using VESTA software. The distribution of charge density on different planes: (b) (110) plane, (c) (001) plane and (d) (011) plane.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/f0587ea7edf6989bf0d5a442.png"},{"id":59509306,"identity":"0e949a12-7df9-44ff-80bb-5e3935af9506","added_by":"auto","created_at":"2024-07-02 15:59:10","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":384148,"visible":true,"origin":"","legend":"\u003cp\u003eThe band structure and total DOS of InAs are calculated with (a)PBE method and (b) HSE06 method. The band structure and total DOS of GaSb are calculated with (c)PBE method and (d) HSE06 method. The calculated band structure and total DOS of 14/7 ML InAs/GaSb SLs with (e)PBE and (f) HSE06 methods. The position of the Fermi level is indicated by the zero point on the horizontal axis.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/4c459c01f5b232094c8a20f2.png"},{"id":59509534,"identity":"cbe6dddc-ace3-4afa-9f38-25b3b14f0f0a","added_by":"auto","created_at":"2024-07-02 16:07:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":880844,"visible":true,"origin":"","legend":"\u003cp\u003eEnergy-dependent optical properties of bulk InAs and GaSb materials, 14/7 ML InAs/GaSb SLs. (a) The real part of the dielectric function. (b) The imaginary part of the dielectric function. (c) Reflectivity. (d) Refractive index. (e) Absorption spectra.\u003c/p\u003e\n\u003cp\u003e(f) Extinction coefficient.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/9670a509bc50abf33f020089.png"},{"id":59509301,"identity":"fd37aa76-ef42-4ddf-967a-2f41eb58eb1e","added_by":"auto","created_at":"2024-07-02 15:59:10","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":132083,"visible":true,"origin":"","legend":"\u003cp\u003eThe absorption, reflectance, and transmittance parameters of (a) a 14/7 ML InAs/GaSb SLs material as obtained through DFT calculations; (b) a ring-square enhanced resonator InAs/GaSb SLs detector, specifically catering to the long-wave range of 8 μm to 14 μm. The impact of material thickness on the efficiency of the LWIR SLs IR-enhanced resonator is also investigated, examining the range of (c) 200 nm to 1000 nm and (d) 2200 nm to 3000 nm.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/ff4a30bdb4749a314904d382.png"},{"id":59510281,"identity":"162ee6eb-e5f6-4e0d-9aa3-a9f0ea5bd6ac","added_by":"auto","created_at":"2024-07-02 16:15:10","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":332613,"visible":true,"origin":"","legend":"\u003cp\u003eThe 2D images of the relationship between SLs thickness, wavelength, and absorptivity for (a) the enhanced long-wave resonator. (b) the enhanced long-wave resonator incorporating SLs. \u0026nbsp;The 2D images of the relationship among the outer radius, wavelength, and absorptivity of a circular-square resonator for (c) the enhanced long-wave resonator and (d) the enhanced long-wave resonator incorporating SLs.\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/4de39a7ca77cd1fb546437d9.png"},{"id":59509305,"identity":"d42d9b7d-e515-43aa-ac36-4d26c2c4c6b9","added_by":"auto","created_at":"2024-07-02 15:59:10","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":757782,"visible":true,"origin":"","legend":"\u003cp\u003eElectric field distribution of XY and YZ plane at 11.2 μm, respectively, with (a) and (d) conventional 2500nm 14/7 ML InAs/GaSb SLs; (b) and (e) the ring resonator; (c) and (f) the ring-square resonator with a \"Φ\" structure.\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/15e86cc1cf3419fbc241ffe7.png"},{"id":63428286,"identity":"b676f98a-14f3-4ed1-8a0e-8d7e60523ab1","added_by":"auto","created_at":"2024-08-28 04:35:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4123258,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4579072/v1/b4bd551b-8ffd-4dda-8071-5465bfb7561b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Design of Resonant Cavity-Enhanced InAs/GaSb Superlattice LWIR Photodetector","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eInfrared detection technology, particularly in the military domain, has undergone significant advancements, propelled by the need for enhanced surveillance, target acquisition, and missile guidance capabilities\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. The longwave infrared window, spanning 8 \u0026micro;m to 14 \u0026micro;m, is critical for night vision applications due to its ability to detect thermal radiation emitted by various objects\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. The discovery of HgCdTe by Lawson et al. in 1959 marked an initial breakthrough in infrared detection. However, issues with the inhomogeneity of its ion-bonded semiconductor alloys, especially in long-wavelength detection, led to decreased detector performance\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. This challenge was addressed in 1977 by Sai-Halasz et al. with the introduction of Type II InAs/GaSb superlattices (SLs)\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Notably, SLs are noted for their tunable bandgap, uniform growth, high absorption coefficient, and efficiency, showing promise in surpassing HgCdTe in long-wave infrared detection within the 8 \u0026micro;m -14 \u0026micro;m range.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAdvancements in infrared detectors have been marked by improved methods for assessing the electronic structure and optical properties of materials. Techniques like the envelope function approximation of the K.P. method, the semi-empirical tight-binding approximation, and the pseudopotential plane wave approximation have been notable\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. However, these conventional methods haven't fully addressed issues related to point defects and interfaces. First-principles calculations offer more precise computation of the electronic structure and optical properties of InAs/GaSb SLs, presenting a new direction for energy band structure optimization\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Furthermore, as device sizes decrease, surface leakage currents, a major contributor to dark current in large-area focal plane arrays, become a significant concern\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. This study focuses on optimizing infrared radiation propagation using a hypersurface structure. Incorporating a resonant cavity on the InAs/GaSb SLs detector's surface generates a localized surface plasmon resonance effect\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, enhancing the coupling of optical radiative energy to the metal surface and directing incident light into an in-plane propagation pattern\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOur research delves into the band structure and optical properties of 14/7 monolayers (ML) InAs/GaSb SLs using first-principles computational methods. These findings are crucial in developing a novel resonant cavity-enhanced \"Φ\" structure for infrared detectors. The study includes a detailed analysis of material simulation, electronic and optical properties, and the application of metasurface resonant cavity in long-wavelength infrared detectors. We establish the 14/7 ML InAs/GaSb SLs structure and investigate its charge density distribution and chemical bond characteristics. The electronic band structure and density of states are calculated for bulk InAs, bulk GaSb, and the 14/7 ML InAs/GaSb SLs using PBE and HSE06 first-principles methods. Optical properties such as reflectance, refractive index, absorption spectrum, and extinction coefficient are primarily determined through the real and imaginary parts of the dielectric function.\u003c/p\u003e \u003cp\u003eA key aspect of our study is designing and analyzing a \"Φ\" structure 14/7 ML InAs/GaSb SLs infrared detector. This design significantly increases absorption efficiency in the LWIR spectrum, notably at 11.2 \u0026micro;m, from 16.48\u0026ndash;99.95%. The phenomenon of enhanced plasmonic resonator perfect absorption in the LWIR SLs is thoroughly analyzed, including detailed electric field distribution within the LWIR photodetector structure. The annular resonators in the \"Φ\" structure induce localized mode-splitting resonance at 11.2 \u0026micro;m, enhancing light absorption. This resonant cavity-enhanced infrared detector demonstrates strong absorption capabilities in the infrared region, suggesting potential applications in long-wavelength SLs focal plane imaging.\u003c/p\u003e"},{"header":"2. Computational Method","content":"\u003cp\u003eThe present research employed the density-functional theory (DFT) from the Vienna ab initio Simulation Package (VASP) for conducting rigorous first-principal calculations\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. The interactions between ions and valence electrons were analyzed using the projector augmented wave (PAW) method\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, and the Perdew-Burke-Ernzerhof (PBE) functional was employed for these calculations\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The band structures and density of states, taking into account the spin-polarized effects of electrons, were calculated using the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functionals\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. A plane wave energy cutoff of 400 eV was set, and convergence criteria for atomic force and energy were established at 0.02 eV and 1\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e eV/\u0026Aring;, respectively. Geometric optimization and band structure calculations were conducted using a 4\u0026times;4\u0026times;4 \u003cb\u003ek\u003c/b\u003e-point mesh for bulk materials, and 2\u0026times;2\u0026times;1 \u003cb\u003ek\u003c/b\u003e-point mesh for supercell 14/7 ML InAs/GaSb SLs.\u003c/p\u003e \u003cp\u003eThe objective of this study is to explore long-wave hypersurface infrared detectors using Type II InAs/GaSb superlattice (SL) materials. We introduced a hypersurface structure that enhances surface plasmon resonance, aimed at increasing absorptivity in the long-wave range. DFT simulations were performed on Type II SL materials to analyze the optical and electrical properties of a periodic InAs/GaSb SL comprising 14 atomic layers of InAs and 7 atomic layers of GaSb. The calculations were conducted with gallium (Ga) as the reference point and indium antimonide (InSb) as the interface layer. Additionally, a metallic hypersurface \"Φ\" structure was simulated atop the device, with specific dimensions and orientation as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a).\u003c/p\u003e \u003cp\u003eThe device structure included a bottom reflective layer made of 100 nm-thick gold (Au), and the absorber layer was composed of a long-wavelength 14/7 ML InAs/GaSb SL, with a periodic thickness of 6.137 nm. A periodic array of \"Φ\" structures was designed with an outer diameter of 900 nm, inner diameter of 410 nm, rectangular structure length (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({l}_{1}\\)\u003c/span\u003e\u003c/span\u003e) of 1900 nm, rectangular structure width (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({l}_{2}\\)\u003c/span\u003e\u003c/span\u003e) of 200 nm, and a counterclockwise 60\u0026deg; angle, as indicated by Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(b). Moreover, the simulation of the infrared detector device is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(c). The device was constructed with a total of 410 cycles, resulting in an overall thickness of approximately 2500 nm, aligning with standard expectations for SLs thickness. Notably, a thin adhesive layer is usually applied between the Au layer and the SLs absorber layer to enhance ohmic contact and prevent metal diffusion. However, experimental calculations revealed that the optical loss of the adhesion layer was found to be extremely negligible. The model was simplified by setting each unit structure to a size of 2000 nm \u0026times; 2000 nm, arranged periodically along the x and y axes to form a periodic array, is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(d). The \"Φ\" structure was instrumental in developing an InAs/GaSb infrared detector with precise optical and electrical properties in the LWIR SLs absorption region, further enhanced through surface plasmon resonance, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(e).\u003c/p\u003e \u003cp\u003eFor accurate simulation of the optical properties of gold in the metal \"Φ\" structures and metal reflectors, the wavelength-domain wave optics module of COMSOL software was utilized. The variation in the dielectric constant of gold with wavelength, as detailed in literature\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, was referenced for this purpose. In the simulation setup, the detector was illuminated with light perpendicular to the x-y plane along the z-axis, allowing for the measurement of reflectance, absorptance, and transmittance, adhering to the equation R\u0026thinsp;+\u0026thinsp;A\u0026thinsp;+\u0026thinsp;T\u0026thinsp;=\u0026thinsp;1\u003csup\u003e10\u003c/sup\u003e. To accurately represent the periodic system, periodic port and periodic boundary conditions were implemented along the x and y axes, ensuring that the propagation of light in the simulation accurately reflected the periodic structure of the system.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Simulation Results and Analysis","content":"\u003cp\u003e \u003cb\u003eA. Electronic Properties of 14/7 ML InAs/GaSb SLs\u003c/b\u003e \u003c/p\u003e \u003cp\u003eCharge density refers to the spatial distribution of electrons, and it has a significant impact on the geometric arrangement and chemical bonding properties of InAs, GaSb, and InSb. By analyzing charge density, we can infer the atomic arrangement of indium (In), arsenic (As), gallium (Ga), and antimony (Sb) on various crystallographic planes. Furthermore, the charge density helps elucidates the nature of chemical bonds, such as ionic or covalent bonds between atoms. For instance, consider the (110) plane as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a). This plane comprises a 7-atom layer of GaSb and a 14-atom layer of InAs, both forming a sphalerite structure characterized by the space group F-43 m\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Within the GaSb layer, each gallium atom is tetrahedrally coordinated to four antimony atoms, and vice versa. The charge density distribution on the (110) plane, depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b), reveals a notable variation in Ga-Sb bond lengths. Initially, the bond length is 2.66 \u0026Aring;, but it extends to 5.088 \u0026Aring; in the subsequent layers\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. This variation is attributed to the lattice constant mismatch, with InAs having a lattice constant of 6.107 \u0026Aring; and GaSb, 6.137 \u0026Aring;, resulting in tensile strain at the GaSb interface. The electron distribution in this map indicates a difference in geometric configuration, particularly at the InAs and GaSb interface where electron clouds are more concentrated around In and Ga atoms, suggesting stronger In-As bonds compared to the weaker Ga-Sb covalent bonds.\u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(c) and (d) display the SLs charge density distribution on the (001) and (011) planes, respectively. The (001) plane predominantly features weak covalent bonds within InAs, characterized by shared electron pairs between InAs atoms, leading to a uniform charge distribution. The outer electron clouds on these facets are incompletely filled, indicative of a weak covalent bonding state. In contrast, the (011) plane, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(d), likely has a denser atomic arrangement due to bonding between surface and internal atoms. The elevated surface energy on this plane causes a more compact charge distribution, thereby increasing the charge density.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a) and (b) display the electronic band structure and density of states for bulk InAs material, bulk GaSb material, and the 14/7 ML InAs/GaSb SLs. These results were obtained by comparing the PBE and HSE06 computational methods. The analysis focuses on the X-Gamma-X path in the first Brillouin zone, with a direct band gap observed at the Gamma point. Notably, the energy band structures are depicted relative to the atomic sizes of the constituent elements. At the Gamma point, the band gap (Eg) represents the energy difference between the valence band's highest energy level (VB) and the lowest energy level in the conduction band (CB). The density of states offers insights into electron distribution across energy levels. Figures\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a) and (b) contrast the band gap energies in zinc blende bulk InAs, while Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(c) and (d) contrast the band gap energies in s zinc blende bulk GaSb, all calculated using PBE and HSE06 methods. PBE calculations suggest negligible band gaps for both InAs and GaSb\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The conduction band energies of InAs are influenced by group V elements, whereas in GaSb, the conduction band is predominantly governed by gallium (Ga), and the valence band by antimony (Sb). The discrepancy in the PBE method is linked to its exchange-correlation energy approximation, which leads to deviations in band gap estimations. For instance, in GaSb and InAs/GaSb SLs, the PBE method inaccurately interchanges the positions of the conduction band top and the valence band bottom, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(e).\u003c/p\u003e \u003cp\u003eTo address the issue of ionization energy shifts common in DFT methods, a novel approach for 14/7 ML InAs/GaSb SLs has been developed, incorporating long-range corrections. The HSE06 method, known for its precision in simulating conduction and valence band behavior in semiconductors, is employed in these calculations. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(b), the energy band structure of InAs shows an energy gap of 0.366 eV, aligning well with existing literature findings\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The InAs conduction band is influenced by both indium (In) and arsenic (As), while the valence band is primarily determined by As. In contrast, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(d) shows that GaSb, despite its zinc blende structure and semiconductor nature, exhibits an energy gap of 0.772 eV, with only slight deviations from previously reported results\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. In GaSb, the conduction band is largely influenced by Ga, with the valence band being affected by both Sb and Ga, though Sb plays a more prominent role. Additionally, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(f) demonstrates that the band structure of the 14/7 ML InAs/GaSb SLs is primarily dictated by Ga and Sb, exhibiting an energy gap of 0.111 eV. This result aligns with calculations using the conventional Kane-Penning (KP) model and falls within the long-wave absorption region's range\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eB. Optical Properties of 14/7 ML InAs/GaSb SLs\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe energy-dependent optical properties of bulk InAs and GaSb materials, as well as 14/7 ML InAs/GaSb SLs. The dielectric function is analyzed in terms of its real and imaginary parts, while reflectivity, refractive index, absorption spectra, and extinction coefficient are also examined by the HSE06 method. Figures\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a) and (b) present the real and imaginary parts of the dielectric constants for bulk InAs, bulk GaSb, and 14/7 ML InAs/GaSb SLs. The real part indicates the material's absorption properties of electromagnetic waves, while the imaginary part reflects the material's ability to dissipate energy in the presence of an electric field\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a), both InAs and GaSb bulk materials exhibit absorption capabilities in the energy range of 0.5-1.0 eV and 2.0-2.5 eV, respectively. However, the 14/7 ML InAs/GaSb superlattices (SLs) exhibit strong absorption of electromagnetic waves with energies below 0.5 eV and demonstrate effective accumulation of charge or polarization. However, the absorption capability of 14/7 ML InAs/GaSb SLs exhibits an exponential decline beyond 0.5 eV, resulting in reduced dielectric loss. This distinctive characteristic significantly diminishes energy loss and signal attenuation, emphasizing the exceptional attributes of these SLs\u003csup\u003e\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b) demonstrates that bulk InAs has strong electric field absorption ability but poor electromagnetic wave transmission ability. The 14/7 ML InAs/GaSb SLs, however, exhibit intermediate properties between the two bulk materials, maintaining strong absorption ability while facilitating better transmission of electric field energy\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c) and (d) display the reflectance and refractive index characteristics of bulk InAs and GaSb, as well as 14/7 ML InAs/GaSb superlattices (SLs). The figures demonstrate that all three materials exhibit a significantly high reflectivity. Among them, the 14/7 ML InAs/GaSb SLs demonstrate a minimum reflectivity of 40%. This finding strongly implies that the superlattice has a pronounced capability for reflecting incident light, while its light absorption potential is limited\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Furthermore, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(d) demonstrates that the refractive indices of bulk InAs and GaSb remain low and constant, whereas the refractive indices of the 14/7 ML InAs/GaSb SLs measure below 0.5 eV, resulting in slower light propagation and higher optical loss. Inspection of the absorption spectra in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(e) reveals the first absorption peaks at 0.417 eV for GaSb and 0.235 eV for InAs materials. These peaks correspond to the energy gap between the highest occupied energy band and the lowest unoccupied energy band, indicative of specific electron transitions, supporting the findings of previous studies. Notably, the absorption peak of the 14/7 ML InAs/GaSb SLs aligns closely with 0.1107 eV, approximately corresponding to the long-wavelength 11.2 \u0026micro;m\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. The presented figure provides visual evidence of the wide spectral response displayed by the superlattice, which aligns with its prominent response peak in the longer wavelength range of 8 \u0026micro;m to 14 \u0026micro;m. Furthermore, it is evident from Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(f) that the 14/7 ML InAs/GaSb superlattice outperforms both bulk InAs and GaSb materials in terms of its remarkable light absorption and scattering capabilities\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003cb\u003eC. Enhanced InAs/GaSb SLs Long-wave Infrared Detector\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eOptical properties\u003c/b\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a) displays the optical performance of 14/7 ML InAs/GaSb SLs in LWIR SLs detectors, particularly focusing on absorptivity, reflectance, and transmittance within the 8 \u0026micro;m to 14 \u0026micro;m wavelength range\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. The figure indicates that the dielectric function of these materials is determined using first-principles calculations. Without any metallic reflector or hypersurface structure, the absorptivity at the 11.2 \u0026micro;m wavelength is relatively low, at about 16.48%. Nonetheless, the material demonstrates high reflectance, exceeding 60% in the 10 \u0026micro;m to 11 \u0026micro;m range, and a significant transmittance of up to 95.03%. In contrast, the \"Φ\" structure metamaterial detector illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b) effectively manipulates the absorbance of the SLs material, significantly decreasing both reflectance and transmittance. With this structure, absorptivity can exceed 99.95%, while reflectivity is reduced to less than 1%, attributable to the minimal transmittance of metallic gold (Au) at the 11.2 \u0026micro;m wavelength. As a result, this enhanced SL structure substantially improves the light absorptivity of the T2SLs detector across a broader spectrum of long-wave infrared radiation\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSimultaneously, we modified the key parameters of the enhanced hypersurface detector with a specific focus on absorptivity. These parameters encompassed the thickness of the 14/7 ML InAs/GaSb SLs (h_T2SLs), the thickness of the gold layers (h_Au and h_Au_bottom), the radii of the rings (r\u003csub\u003e1\u003c/sub\u003e and r\u003csub\u003e2\u003c/sub\u003e), and the dimensions and angles of the rectangles on the rings (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({l}_{1}\\)\u003c/span\u003e\u003c/span\u003e, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({l}_{2}\\)\u003c/span\u003e\u003c/span\u003e, and angle). Absorptivity, especially influenced by the thickness of the SLs material, affects both the absorption wavelength range and intensity\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(c) shows that within a thickness range of 200 nm to 1000 nm, a SLs with a thickness of 200 nm achieved an absorptivity of up to 99%, but with a narrower wavelength half-width of 0.7 eV. However, when the SLs material was too thin, the gold layers on the surface predominantly absorbed the light, leading to a decrease in light absorptivity by more than 10% for every 100 nm increase in thickness. Furthermore, Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(d) demonstrates that selecting a material thickness in the range of 2300 nm to 3000 nm narrows the wavelength range between 11 \u0026micro;m and 11.5 \u0026micro;m. Increasing the thickness causes a red-shift in the wavelength, with an absorptivity exceeding 99% and a wavelength half-width of around 0.1 eV observed at a thickness of 2500 nm. This finding highlights the crucial impact of SLs thickness on absorptivity, with optimal absorption achieved around a thickness of 2500 nm.\u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a) and (b) showcase two-dimensional absorption spectroscopy images, providing insights into the enhanced plasmonic structures and SLs materials. These images are instrumental in intuitively optimizing and analyzing how the thickness of SLs materials influences the intensity and wavelength of light absorption. In Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a), it can be observed that within the wavelength range of 9 \u0026micro;m to 11.5 \u0026micro;m, the absorptivity is higher than 70%. The absorption is predominantly concentrated around the 11 \u0026micro;m wavelength, thereby amplifying the effect\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(b) indicates that the light absorption intensity of SLs with an enhanced plasmonic structure is mainly significant for thicknesses of 1500 nm and above. It appears that the gold (Au) material, particularly within a thickness of 500 nm, contributes significantly to the absorptivity. However, a single layer of SLs material, at a thickness of 2300 nm or more, achieves an absorptivity of 76.35% at the 11.2 \u0026micro;m wavelength. This level of absorption represents a substantial increase, nearly five times higher, compared to a single 14/7 ML InAs/GaSb SLs. Further details are provided in Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(c) and (d), which illustrate the absorption spectra of the enhanced plasmonic structure and SLs across various outer diameters and wavelengths\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(c) shows that changes in the outer diameter have a minimal impact on the wavelength. The enhanced plasmonic structure demonstrates peak light absorption when the radius exceeds 600 nm. Conversely, as per Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(d), the SLs exhibit a similar absorption pattern but cease to absorb light effectively for a radius exceeding 920 nm. This pattern underlines the influence of structural dimensions on the light absorption capabilities of these materials\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e \u003cb\u003eElectric field analysis\u003c/b\u003e \u003c/p\u003e \u003cp\u003eTo comprehensively understand the perfect absorption phenomenon induced in LWIR SLs using an enhanced plasma resonator, it is essential to examine the effect of localized electric field enhancement on the underlying physical mechanism. This understanding can be achieved through a comprehensive analysis of the electric field distribution across the entire LWIR photodetector structure. Figures\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a) to (c) display the electric field distribution in the XY plane, while Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(d) to (f) present the distribution in the YZ plane. In these illustrations, the planes are positioned at either an X or Z coordinate of 50 nm. The plots utilize red and blue colors to represent the strongest and weakest electric fields. Figures\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a) and (d) depict the electric field distribution on the surface and cross-section of the SLs without the resonator and metal reflection layer. In these scenarios, the electric field on the surface is uniformly distributed, but the cross-sectional field is predominantly absorbed at the surface, with minimal penetration into the SLs\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Conversely, Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(c) and (e) show the electric field at the interface of the ring resonator and the SLs. Here, the electric field is intensely concentrated at the junction of the resonator and the SLs surface, coinciding with the highest field intensity area. This pattern suggests that the surface-iso-excitation resonance confines the incident light's energy primarily within the metallic Au layer\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Furthermore, Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(c) and (f) demonstrate that in the ring-square resonator, the electric field is mainly focused within the inner region of the SLs material. This configuration not only enhances the field's intensity but also establishes a continuous current flow between the resonator layer and the Au reflecting layer, creating a loop current between these metal layers\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. This localized enhancement is sustained throughout the 14/7 ML long-wavelength InAs/GaSb SLs depletion layer in the detector. Consequently, the ring-square resonator with a \"Φ\" structure efficiently excites a localized equipartitioned exciton resonance at a wavelength of 11.2 \u0026micro;m. This result underscores the importance of resonator design in optimizing the photodetection capabilities of the LWIR SLs detectors.\u003c/p\u003e "},{"header":"4. Conclusion","content":"\u003cp\u003eIn conclusion, we have presented a comprehensive analysis of material simulation, electronic and optical properties, and the integration of metasurface resonant cavities in long-wavelength infrared detectors. Employing first-principles computational methods, we examined the band structure and optical characteristics of 14/7 ML InAs/GaSb SLs, which were facilitated the development of a \"Φ\" structure infrared detector, enhanced by a resonant cavity. We successfully determined the energy gaps of 0.366 eV for InAs and 0.772 eV for GaSb utilizing the HSE06 method. Additionally, the band structure analysis of the 14/7 ML InAs/GaSb SLs further indicated an energy gap of 0.111 eV, effectively placing it within the desired longwave absorption region. Furthermore, we designed a detector that demonstrates exceptional absorption capabilities, achieving absorption efficiency in the LWIR spectrum, notably at 11.2 \u0026micro;m, from 16.48\u0026ndash;76.35%. Our research included an in-depth examination of the electric field distribution within the detector structure, as well as an analysis of the phenomena associated with the enhanced plasmonic resonator and its perfect absorption capability. These findings confirm the substantial absorption potential of the resonant cavity-enhanced infrared detector. The results highlight the detector's promising applications in long-wavelength SLs focal plane imaging systems, marking a significant advancement in the field of infrared detection technology.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e R.G. made the basic simulation and wrote the manuscript. Z.L. re-viewed and edited the final draft of the manuscript. X.Z. and Q.F contributed to basic conceptualization. B.L., Y.C., and Y.Z. helped in the theoretical analysis and the interpretation of the results. Y.C., Q.F., and X.Z provided useful advice and assistance. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u0026nbsp;\u003c/strong\u003eThis work was supported by the Beijing Scholars Program (Grant No. BJXZ20210016), National Natural Science Foundation of China (Grant No.62205029), 111 Project of China (D21009).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u0026nbsp;\u003c/strong\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompliance with ethical standards:\u0026nbsp;\u003c/strong\u003eAll data generated or analysed during this study are included in this published article. The datasets used and analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRazeghi, M. \u003cem\u003eet al.\u003c/em\u003e Type-II InAs/GaSb photodiodes and focal plane arrays aimed at high operating temperatures. Opto-Electronics Review 19, (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaddadi, A. \u003cem\u003eet al.\u003c/em\u003e Low frequency noise in 1024x1024 long wavelength infrared focal plane array based on type-II InAs/GaSb superlattice. in \u003cem\u003eQuantum Sensing and Nanophotonic Devices IX\u003c/em\u003e vol. 8268 199\u0026ndash;204 (SPIE, 2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRazeghi, M. \u003cem\u003eet al.\u003c/em\u003e Recent advances in LWIR Type-II InAs/GaSb superlattice photodetectors and focal plane arrays at the center for quantum devices. 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Sci Rep 7, 430 (2017).\u003c/span\u003e\u003c/li\u003e\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":"Type-II superlattice detectors, First principle, resonant cavity-enhanced infrared detector, long-wavelength infrared","lastPublishedDoi":"10.21203/rs.3.rs-4579072/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4579072/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eType-II superlattices (T2SLs) have recently emerged as a focal point in long-wavelength infrared (LWIR) detection, showcasing remarkable potential across various applications. In this work, we have revealed a theoretical investigation into the band structure and optical properties of 14/7 ML InAs/GaSb SLs, employing density functional theory (DFT). Our findings show that the energy gap of these SLs is determined to be 0.111 eV through energy band structure analysis by the HSE06 method. Moreover, we have designed a resonant cavity-enhanced \"Φ\" structure for the 14/7 ML InAs/GaSb SLs infrared detector. This innovative design markedly enhances absorption efficiency, increasing it from 16.48% to an impressive 76.35% at the 11.2 \u0026micro;m wavelength. Further analysis includes a detailed examination of the electric field distribution within this structure and a comprehensive examination of the enhanced plasmonic resonator's perfect absorption phenomenon. The results from these analyses underscore the exceptional absorption capabilities of our resonant cavity-enhanced infrared detector, indicating its potential for significant applications in LWIR SLs focal plane.\u003c/p\u003e","manuscriptTitle":"Design of Resonant Cavity-Enhanced InAs/GaSb Superlattice LWIR Photodetector","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-02 15:59:05","doi":"10.21203/rs.3.rs-4579072/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":"178bfcc1-9f80-4a3a-9edc-0672f613b6d2","owner":[],"postedDate":"July 2nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":33982892,"name":"Physical sciences/Materials science/Materials for optics/Metamaterials"},{"id":33982893,"name":"Physical sciences/Mathematics and computing/Computational science"}],"tags":[],"updatedAt":"2024-08-28T04:27:47+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-02 15:59:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4579072","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4579072","identity":"rs-4579072","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}