Single-Molecule Magnet Bridging Along Exposed Sidewalls of Metal–Insulator–Semiconductor Diodes for Molecular Transport Studies

Single-Molecule Magnet Bridging Along Exposed Sidewalls of Metal–Insulator–Semiconductor Diodes for Molecular Transport Studies | 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 Single-Molecule Magnet Bridging Along Exposed Sidewalls of Metal–Insulator–Semiconductor Diodes for Molecular Transport Studies Pius Kika Suh, Babu Ram Sankhi, Carlos Rojas-Dotti, José Martínez-Lillo, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7821044/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Single-Molecule Magnets (SMMs) are promising for molecular spintronics owing to their quantum properties; however, reproducible integration into devices has remained challenging due to limitations of break-junction and gold-based systems. This study introduces a scalable NiFe/AlOx/p-Si Metal–Insulator–Semiconductor (MIS) platform that enables reliable sidewall bridging of lipoic acid–functionalized Mn₆ SMMs through disulfide linkages. Despite fabrication-related variability in pristine MIS junctions, molecular integration produced convergent tunneling characteristics across multiple devices, as confirmed by standard deviation analysis, thus addressing reproducibility issues common in molecular systems. Kelvin Probe Force Microscopy (KPFM) revealed an approximately 0.4 V increase in NiFe surface potential following SMM attachment, providing electrode-level evidence of molecular influence. Conceptual modeling suggests two cooperative mechanisms: (i) orbital-assisted tunneling that reduces effective barrier height and enhances interfacial density of states, and (ii) charge redistribution at the NiFe/SMM interface, resulting in band flattening and surface potential rise. These mechanisms collectively account for the reproducibility and interfacial modifications observed experimentally. Although spin-selective transport awaits direct confirmation, the demonstrated reproducibility and scalability establish this MIS–SMM architecture as a robust testbed for molecular integration and a viable route toward spintronic device applications. The study provides immediate relevance for molecular electronics and defines a foundation for advanced investigations using complementary low-temperature and magnetic characterization methods such as SQUID magnetometry, EPR spectroscopy, and magneto-transport. Physical sciences/Materials science Physical sciences/Nanoscience and technology Physical sciences/Physics Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Introduction Molecular-scale electronics and spintronics aim to exploit the unique functionalities of molecules to achieve device behaviors beyond conventional semiconductors [1-3]. Among these, Single-Molecule Magnets (SMMs) stand out for their quantum properties, including magnetic bistability, spin blockade, and slow relaxation, which make them promising candidates for molecular spintronic applications [4, 5]. Despite this potential, reliably integrating SMMs into reproducible device architectures remains a major challenge. Their large size, chemical sensitivity, and variability in electrode bonding interactions often result in poor yield, limited scalability, and inconsistent device behavior [6]. Over the past two decades, break-junction devices and gold-based electrodes have been the dominant approaches for probing SMM transport [7, 8]. These studies revealed intriguing single-molecule effects but remain constrained by poor reproducibility, uncertain molecule–electrode bonding, and the fragility of gold electrodes [9]. Similar challenges have been emphasized in recent reviews highlighting the persistent reproducibility and interface problems in molecular spintronics [10]. Self-assembled monolayers on metallic electrodes have also been investigated [11, 12], but pinholes, short-circuit pathways, and monolayer variability reduce reliability for transport studies [13]. Protecting groups are often required to prevent thiol-based SMMs from undergoing undesirable inter- and intramolecular interactions, further complicating fabrication [14, 15]. Recent reports demonstrated the feasibility of molecular channel formation using liftoff-exposed side edges in both magnetic tunnel junction (MTJ) and MIS-based devices [16, 17]. While these studies established proof-of-concept sidewall bridging, they also highlighted persistent challenges of reproducibility and practical scalability. Electrode design has further been shown to critically influence molecular coupling and device stability [18], and interface mismatches can cause molecules to lose their functional identity when bound to certain magnetic electrodes [19]. These findings underscore the importance of robust testbeds capable of both scalable fabrication and reliable molecular integration. In this work, we present a NiFe/AlOx/p-Si Metal–Insulator–Semiconductor (MIS) platform with side-exposed geometries that enables reproducible SMM bridging through disulfide functionalization. Unlike gold-based break junctions, this testbed relies solely on conventional photolithography and thin-film deposition, making it compatible with large-scale fabrication and diverse electrode materials. Electrical transport measurements reveal reproducible enhancement following SMM integration across devices with variable baseline tunneling currents. Independent Kelvin Probe Force Microscopy (KPFM) confirms that SMM channels alter the surface potential of the NiFe electrode [20], providing electrode-level validation of molecular influence. Finally, conceptual modeling links these effects to orbital-assisted tunneling and charge redistribution[19], offering a mechanistic framework for understanding the reproducibility of molecularly modified MIS junctions. By combining reproducible transport data, electrode-level characterization, and mechanistic interpretation, this study establishes the MIS–SMM platform as a scalable testbed for molecular quantum materials. Although spin-selective transport remains to be confirmed, recent studies suggest that complementary magnetic and low-temperature techniques will be critical for capturing spin-dependent phenomena[21, 22]. Together, these results highlight a reproducible, scalable, and conceptually grounded strategy for advancing SMM-based molecular spintronics. 2. Methodology NiFe/AlOx/p-Si metal–insulator–semiconductor (MIS) junctions were fabricated using standard photolithography and thin-film deposition (Fig. 1) [23]. p-type Si (100) wafers (Fig.1a) were patterned via photolithography and etched in buffered HF solution to expose the semiconductor surface (Fig.1b). A 2 nm AlOx layer was deposited by RF sputtering, using the AJA International sputtering machine (Fig. 1c), followed by a ~15 nm NiFe top electrode deposited under Argon plasma. Liftoff was performed in Micro posit 1165 solution, yielding cross-junction devices with exposed sidewalls (Fig.1d). Current–voltage (I–V) characteristics were recorded on a micromanipulator probe station using a Keithley 6430 Sub-Femtoampere Remote Source Meter. Baseline I–V curves were obtained for MIS junctions prior to molecular attachment, with tunneling behavior interpreted using Brinkman’s model Lipoic acid–functionalized Mn₆ SMMs were attached by immersing devices in a 0.1 mM ethanol solution for ~2 minutes while applying alternating ±0.2 V bias to assist electrophoretic alignment, consistent with prior molecular junction studies that employed sub-millimolar concentrations to balance surface coverage and reproducibility [23-25]. Control studies, consistent with our prior demonstrations of molecular coupling effects in spintronic junctions [26], confirmed that only sidewall-bridged molecules contributed to transport, while surface-adsorbed species had negligible effect. The robustness of thiol/disulfide chemistry for electrode functionalization has also been well established in self-assembled monolayer studies [27]. Kelvin Probe Force Microscopy (KPFM) measurements were performed on a NaioFlex AFM system to map electrode surface potentials before and after molecular bridging [28]. I–V data were fitted using Brinkman’s tunneling model and the diode transport equation to extract barrier thickness, barrier height, and ideality factors. Solvent and interfacial effects were interpreted within the framework of prior studies of molecular environments [29]. These fabrication and characterization steps established the baseline necessary to evaluate the reproducibility and electrode-level impact of SMM integration. 3. Results and Discussion Current–voltage (I–V) measurements of NiFe/AlOx/p-Si junctions revealed significant modulation after SMM integration. Baseline MIS devices showed variability in tunneling current due to differences in AlOx barrier quality, as expected from fabrication tolerances. Figures 2a–e show representative I–V curves for five junctions (J1–J5). While the bare devices exhibited diverse current levels, after SMM bridging, all junctions displayed remarkably consistent transport behavior. This reproducibility was further validated by averaging transport characteristics across the five junctions (Figure 2f). The standard deviation in current decreased significantly after SMM attachment, confirming that molecular bridging yields uniform transport modulation independent of initial device variability. These findings demonstrate that SMMs establish stable and reproducible transport channels across multiple devices, strengthening the case for their integration into scalable device architectures. To complement the electrical transport measurements, we performed Kelvin Probe Force Microscopy (KPFM) to map the surface potential before and after SMM attachment. As shown in Figure 3a, the pristine MIS device exhibited modest potential differences between NiFe, AlOx, and p-Si regions. After SMM integration (Figure 3b), a pronounced rise in NiFe electrode surface potential was observed. A line scan across the junction (Figure 3c) quantified this increase at approximately 0.4 V. The localized shift was most prominent at the junction region, consistent with SMM bridging at the exposed sidewalls. Importantly, the p-Si electrode potential remained largely unchanged, confirming that the modification arises from SMM–NiFe coupling rather than substrate effects. This independent surface-potential evidence reinforces the transport data and rules out alternative explanations such as oxide defects. These findings suggest that SMM channels not only act as additional tunneling pathways but also alter the interfacial properties of NiFe. To better interpret the transport reproducibility and the observed ~0.4 V shift in surface potential, we developed a conceptual mechanism as illustrated in Figure 4. Although the present measurements were conducted at room temperature and do not capture spin-selective transport directly, the observed electrode-level modulation establishes a platform that can be extended with complementary techniques such as SQUID magnetometry, EPR spectroscopy, and low-temperature magneto-transport. By focusing on reproducibility and scalability while acknowledging the need for direct magnetic evidence, this study positions the MIS–SMM platform as both a practical molecular testbed and a steppingstone toward spintronic device applications To rationalize these experimental observations, we propose a conceptual mechanism that highlights the role of SMM channels in MIS transport modulation (Figure 4). In the pristine NiFe/AlOx/p-Si structure (Figure 4a), electron conduction is dominated by tunneling through the AlOx barrier, with effective barrier properties varying due to fabrication tolerances. This variability explains the device-to-device differences in baseline I–V curves. After SMM functionalization (Figure 4b), robust disulfide anchoring enables molecular bridging between NiFe and p-Si. These molecules introduce orbital-assisted tunneling pathways via their LUMO levels, lowering the effective barrier height and increasing the local density of states (DOS) at the interface. As a result, electrons hop into SMM orbitals and tunnel through, producing enhanced and reproducible current across devices. Charge redistribution at the NiFe/SMM interface further modifies the electrode surface potential, consistent with the ~0.4 V increase detected by KPFM. Together, these complementary effects provide a mechanistic explanation for both the reproducible transport enhancement and the electrode-level modification observed after SMM integration. 4. Conclusion We have demonstrated that sidewall bridging of lipoic acid–functionalized Mn₆ SMMs transforms NiFe/AlOx/p-Si MIS junctions into reproducible molecular tunneling devices. Despite baseline variability in AlOx tunneling responses, molecular integration produced convergent I–V characteristics across multiple devices, confirming that SMM channels dominate transport behavior. Kelvin Probe Force Microscopy revealed a ~0.4 V shift in NiFe surface potential after molecular attachment, while Brinkman model analysis verified uniform barrier parameters, reinforcing the robustness of the molecular effect. Together, these results establish reproducibility and scalability as defining features of the MIS–SMM platform. Although direct spin-selective transport was not obtained here, the reproducibility of device-level modulation and electrode sensitivity demonstrated by KPFM position this architecture as a practical molecular testbed and a foundation for future spintronic applications. Future studies employing low-temperature magneto-transport, SQUID magnetometry, and EPR spectroscopy will be critical to directly probe spin-dependent phenomena and further advance the spintronic potential of MIS–SMM systems. Declarations Acknowledgments We gratefully acknowledge the funding support from the National Science Foundation-CREST Award (Contract # HRD-1914751), NSF-MRI grant 1920097, Department of Energy/National Nuclear Security Agency (DE-FOA-0003945), and NASA MURP grant (80NSSC19M0196), at the Center for Nanotechnology Research and Education (CNRE), University of the District of Columbia. Thanks to Prof. Pawan Tyagi for mentorship and scientific guidance, Dr. José Martínez-Lillo and Dr. Carlos Rojas-Dotti at the University of Valencia (ICMol) for providing Single-Molecule Magnet samples and valuable discussions, and Mr. Hayden Brown for technical assistance with thin-film deposition and cleanroom operations. Conflict of Interest There is no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding Declaration This research was supported by the National Science Foundation-CREST Award (Contract # HRD-1914751), NSF-MRI grant 1920097, Department of Energy/National Nuclear Security Agency (DE-FOA-0003945), and NASA MURP grant (80NSSC19M0196). The funding bodies had no role in the design of the study; in the collection, analysis, or interpretation of data; or in the writing of the manuscript. Data Availability Statement The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. References Bogani, L. and W. Wernsdorfer, Molecular spintronics using single-molecule magnets. Nature Materials, 2008. 7 (3): p. 179-186. Christou, G., et al., Single-molecule magnets. MRS Bulletin, 2000. 25 (11): p. 66-71. Si, W., et al., Single-molecule non-volatile memories: an overview and future perspectives. Journal of Materials Chemistry C, 2024. Zhu, Z. and et al., Air-stable chiral single-molecule magnets with record anisotropy barrier exceeding 1800 K. Journal of the American Chemical Society, 2021. 143 (27): p. 10077-10082. Chen, G.X., et al., Electronic and magnetic properties of MoI3 monolayer effected by point defects and rare earth metal doping. Journal of Physics and Chemistry of Solids, 2025. 199 : p. 112508. Gehring, P., J.M. Thijssen, and H.S.J. van der Zant, Single-molecule quantum-transport phenomena in break junctions. Nature Reviews Physics, 2019. 1 (6): p. 381-396. Heersche, H.B. and et al., Electron transport through single Mn12 molecular magnets. Physical Review Letters, 2006. 96 (20): p. 206801. Wang, F. and et al., Electrically controlled nonvolatile switching of single-atom magnetism in a Dy@C84 single-molecule transistor. Nature Communications, 2024. 15 (1): p. 2450. Xu, G. and et al., Challenges and prospects of molecular spintronics. Journal of Materials Chemistry C, 2023. 11 : p. 2645-2665. Li, D.F., et al., Ancillary Ligand Functionalization of Cyanide-Bridged S = 6 FeIII4NiII4 Complexes for Molecule-Based Electronics. Inorganic Chemistry, 2006. 45 (13): p. 7569-7578. Rojas-Dotti, C. and J. Martínez-Lillo, Thioester-functionalised and oxime-based hexametallic manganese (III) single-molecule magnets. RSC Advances, 2017. 7 (77): p. 48841-48847. Orts-Arroyo, M., et al., Lipoic Acid-Functionalized Hexanuclear Manganese(III) Nanomagnets Suitable for Surface Grafting. International Journal of Molecular Sciences, 2023. 24 (10): p. 8645. Tyagi, P., et al., Molecular Electrodes At The Exposed Edge Of Metal/Insulator/Metal Trilayer Structures. Journal of the American Chemical Society, 2007. 129 (16): p. 4929-4938. Tyagi, P. and C. Riso, Magnetic force microscopy revealing long range molecule impact on magnetic tunnel junction based molecular spintronics devices. Organic Electronics, 2019. 75 : p. 105421. Barra, A.L. and et al., New single-molecule magnets by site-specific substitution: Incorporation of "Alligator clips" into Fe-4 complexes. European Journal of Inorganic Chemistry, 2007(26): p. 4145-4152. Savadkoohi, M., et al., Spin Solar Cell Phenomenon on a Single-Molecule Magnet (SMM) Impacted CoFeB-Based Magnetic Tunnel Junctions. ACS Applied Electronic Materials, 2023. 5 (6): p. 3333-3339. Mutunga, E. and et al., Magnetic molecules lose identity when connected to different combinations of magnetic metal electrodes in MTJ-based molecular spintronics devices. Scientific Reports, 2023. 13 : p. 17128. Savadkoohi, M. and et al., Increasing ferromagnet electrode thickness prevented molecular coupling producing room temperature stable current suppression. Journal of Applied Physics, 2022. 131 : p. 013901. Wu, X. and J. Davis, Surface Potential Measurement Using KPFM. Journal of Applied Physics, 2020. 128 (9): p. 091101. Brinkman, W.F., R.C. Dynes, and J.M. Rowell, Tunneling conductance of asymmetrical barriers. Journal of Applied Physics, 1970. 41 (5): p. 1915-1921. Xu, L. and et al., A review on footsteps of a revolution in electronics: Spin memristors. Advanced Materials, 2025. 37 : p. 2500116. Savadkoohi, M. and et al., Single-Molecule Magnet’s (SMM) effects on spin-dependent transport in antiferromagnet-based MTJ molecular spintronic devices. AIP Advances, 2025. 15 (3): p. 035035. Sankhi, S. and P. Tyagi, Mass-Scale Molecular Spintronics Devices Using Liftoff-Exposed Side Edges of Magnetic Tunnel Junctions. RSC Advances, 2020. 10 : p. 13006-13015. Park, J., et al., Coulomb Blockade and the Kondo Effect in Single-Atom Transistors. Nature, 2002. 417 : p. 722-725. Heersche, H.B., et al., Electrical Detection of Single-Molecule Magnetic Hysteresis. Physical Review Letters, 2006. 96 : p. 206801. Tyagi, P., et al., Intra-Molecular Coupling within Double-Segmented Molecules Impacting Magnetic Tunnel Junction-Based Molecular Spintronics Devices. MRS Communications, 2024. 14 : p. 103-113. Love, J.C., et al., Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology. Chemical Reviews, 2005. 105 : p. 1103-1170. Melitz, W., et al., Kelvin Probe Force Microscopy and Its Application. Surface Science Reports, 2011. 66 : p. 1-27. Reichardt, C. and T. Welton, Solvents and Solvent Effects in Organic Chemistry, 4th ed . 2011, Weinheim: Wiley-VCH. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 27 Jan, 2026 Reviews received at journal 23 Jan, 2026 Reviewers agreed at journal 15 Jan, 2026 Reviews received at journal 07 Jan, 2026 Reviewers agreed at journal 05 Jan, 2026 Reviewers invited by journal 15 Oct, 2025 Editor assigned by journal 15 Oct, 2025 Editor invited by journal 15 Oct, 2025 Submission checks completed at journal 14 Oct, 2025 First submitted to journal 14 Oct, 2025 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-7821044","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":534854404,"identity":"92cb2ba1-eff0-4c77-bd1b-789be7d3a251","order_by":0,"name":"Pius Kika Suh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAt0lEQVRIiWNgGAWjYDACZgiVwM/AYIDgEqVFsoFoLVCQYHCAWC3m7DzGHxj+HM4zvpG88QNDhXViAyEtls08ZhKMbYeLzW6kFUswnEknrMXgMI8ZA2PD4cRtN3KAjLbDRGkBOyxx8wyQln/EaTGQYGA7nLhBIgdiHRF+YSuTSGxLT5xx5lmxRMKxdGOCWsz5D2/+8OGPdWJ/OzDEPtRYyxJ2GIhIgPEScCnD0DIKRsEoGAWjAC8AAEcoPEjllJ6UAAAAAElFTkSuQmCC","orcid":"","institution":"University of the District of Columbia","correspondingAuthor":true,"prefix":"","firstName":"Pius","middleName":"Kika","lastName":"Suh","suffix":""},{"id":534854405,"identity":"9872ffcd-e02b-43d6-a9eb-a086e9584ebc","order_by":1,"name":"Babu Ram Sankhi","email":"","orcid":"","institution":"University of the District of Columbia","correspondingAuthor":false,"prefix":"","firstName":"Babu","middleName":"Ram","lastName":"Sankhi","suffix":""},{"id":534854406,"identity":"3b7bd30d-763f-4563-994b-1416c417d48b","order_by":2,"name":"Carlos Rojas-Dotti","email":"","orcid":"","institution":"University of Valencia","correspondingAuthor":false,"prefix":"","firstName":"Carlos","middleName":"","lastName":"Rojas-Dotti","suffix":""},{"id":534854407,"identity":"523b6511-5394-4a84-b10c-f7ac47923f14","order_by":3,"name":"José Martínez-Lillo","email":"","orcid":"","institution":"University of Valencia","correspondingAuthor":false,"prefix":"","firstName":"José","middleName":"","lastName":"Martínez-Lillo","suffix":""},{"id":534854408,"identity":"b3e3f03e-deab-4143-b2dc-a012c875a5a0","order_by":4,"name":"Pawan Tyagi","email":"","orcid":"","institution":"University of the District of Columbia","correspondingAuthor":false,"prefix":"","firstName":"Pawan","middleName":"","lastName":"Tyagi","suffix":""}],"badges":[],"createdAt":"2025-10-09 22:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7821044/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7821044/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":94680693,"identity":"7fbe4659-a32b-4177-8fb3-b89595fbd78f","added_by":"auto","created_at":"2025-10-29 14:43:20","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2901276,"visible":true,"origin":"","legend":"\u003cp\u003eFabrication and molecular functionalization of NiFe/AlOx/p-Si MIS junctions with sidewall-bridged SMMs.\u003cbr\u003e\n(a–d) Schematic fabrication sequence: SiO₂-covered p-Si substrate, selective etching to expose Si, deposition of ~2 nm AlOx and ~15 nm NiFe by RF sputtering, and liftoff to define cross-junction geometry with exposed sidewalls.\u003cbr\u003e\n(e,f) Electrophoretically assisted assembly of lipoic acid–functionalized Mn₆ SMMs across the sidewall gap, enabling reproducible molecular transport channels between NiFe and Si.\u003cbr\u003e\n(g) SEM micrograph of a representative MIS junction highlighting the NiFe and SiO₂ layers.\u003cbr\u003e\n(h) Molecular structure of the lipoic acid–functionalized Mn₆ SMM used for integration.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7821044/v1/54681954b98ff7e36e2a95ea.png"},{"id":94680694,"identity":"4a04200b-610f-4c4a-b156-0d168eb7603d","added_by":"auto","created_at":"2025-10-29 14:43:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1508156,"visible":true,"origin":"","legend":"\u003cp\u003eTunneling current before and after Single-Molecule Magnet (SMM) functionalization in NiFe/AlOx/p-Si MIS junctions.\u003cbr\u003e\n(a–e) Current–voltage (I–V) characteristics of five independent junctions (J1–J5) recorded before (gray squares) and after (red circles) attachment of lipoic acid–functionalized SMMs. Following a brief electrophoretically assisted immersion process, disulfide linkages enabled stable bridging of the molecules across the exposed sidewall gaps of the junctions. Consistent increases in tunneling current were observed across all devices, despite baseline variability between junctions, confirming robust integration of SMM channels into the tunneling pathway. (f) Standard deviation of tunneling current across the junction set before (blue) and after (red) SMM functionalization, demonstrating reproducibility of the enhancement effect and a systematic reduction of junction-to-junction variability at forward bias. Error bars represent standard deviations from repeated measurements. Together, these results highlight the reproducible modulation of tunneling transport achieved through molecular integration into scalable MIS architectures\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7821044/v1/f9b68725d9e47c7408afd36b.png"},{"id":94727982,"identity":"0b47ab7e-79ef-4b2d-965c-f4597d03ce51","added_by":"auto","created_at":"2025-10-30 07:02:38","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":3954157,"visible":true,"origin":"","legend":"\u003cp\u003eKelvin Probe Force Microscopy (KPFM) mapping of surface potential in NiFe/AlOx/p-Si MIS junctions before and after Single-Molecule Magnet (SMM) functionalization.\u003cbr\u003e\n(a) Surface potential (S. potential) distribution prior to molecular attachment, showing distinct contrast between top NiFe electrode, bottom electrode, and exposed SiO₂ layer. (b) After SMM integration, the NiFe top electrode exhibits a pronounced increase in surface potential, consistent with charge transfer and dipolar contributions from the anchored molecules. (c) Line profile comparison along L1 confirms a systematic rise of ~0.4 V in electrode potential after functionalization, validating the molecular influence on interfacial electronic structure.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7821044/v1/3bb2eb700c5fc5c22e4a4928.png"},{"id":94680691,"identity":"2d57233e-eaef-40a5-bfd5-17ea8649bcb8","added_by":"auto","created_at":"2025-10-29 14:43:20","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":554527,"visible":true,"origin":"","legend":"\u003cp\u003eConceptual mechanism for SMM-mediated transport in NiFe/AlOx/p-Si MIS junctions. (a) Pristine MIS with tunneling dominated by the AlOx barrier. (b) SMM bridging introduces molecular channels that increase interfacial DOS. (c) Orbital-assisted tunneling via SMM LUMO levels lowers the effective barrier height. (d) Charge redistribution at the NiFe/SMM interface produces band flattening, consistent with the ~0.4 V KPFM shift.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7821044/v1/59f55af8f24299a3905b1b61.png"},{"id":94731081,"identity":"d02fd5fd-e196-4516-aec2-eab7af221ec2","added_by":"auto","created_at":"2025-10-30 07:07:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5484424,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7821044/v1/a2e30a03-d1d7-46b7-8d60-93bdde1888b3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Single-Molecule Magnet Bridging Along Exposed Sidewalls of Metal–Insulator–Semiconductor Diodes for Molecular Transport Studies","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eMolecular-scale electronics and spintronics aim to exploit the unique functionalities of molecules to achieve device behaviors beyond conventional semiconductors [1-3]. Among these, Single-Molecule Magnets (SMMs) stand out for their quantum properties, including magnetic bistability, spin blockade, and slow relaxation, which make them promising candidates for molecular spintronic applications [4, 5]. Despite this potential, reliably integrating SMMs into reproducible device architectures remains a major challenge. Their large size, chemical sensitivity, and variability in electrode bonding interactions often result in poor yield, limited scalability, and inconsistent device behavior [6].\u003c/p\u003e\n\u003cp\u003eOver the past two decades, break-junction devices and gold-based electrodes have been the dominant approaches for probing SMM transport [7, 8]. These studies revealed intriguing single-molecule effects but remain constrained by poor reproducibility, uncertain molecule\u0026ndash;electrode bonding, and the fragility of gold electrodes [9]. Similar challenges have been emphasized in recent reviews highlighting the persistent reproducibility and interface problems in molecular spintronics [10]. Self-assembled monolayers on metallic electrodes have also been investigated [11, 12], but pinholes, short-circuit pathways, and monolayer variability reduce reliability for transport studies [13]. Protecting groups are often required to prevent thiol-based SMMs from undergoing undesirable inter- and intramolecular interactions, further complicating fabrication [14, 15].\u003c/p\u003e\n\u003cp\u003eRecent reports demonstrated the feasibility of molecular channel formation using liftoff-exposed side edges in both magnetic tunnel junction (MTJ) and MIS-based devices [16, 17]. While these studies established proof-of-concept sidewall bridging, they also highlighted persistent challenges of reproducibility and practical scalability. Electrode design has further been shown to critically influence molecular coupling and device stability [18], and interface mismatches can cause molecules to lose their functional identity when bound to certain magnetic electrodes [19]. These findings underscore the importance of robust testbeds capable of both scalable fabrication and reliable molecular integration.\u003c/p\u003e\n\u003cp\u003eIn this work, we present a NiFe/AlOx/p-Si Metal\u0026ndash;Insulator\u0026ndash;Semiconductor (MIS) platform with side-exposed geometries that enables reproducible SMM bridging through disulfide functionalization. Unlike gold-based break junctions, this testbed relies solely on conventional photolithography and thin-film deposition, making it compatible with large-scale fabrication and diverse electrode materials. Electrical transport measurements reveal reproducible enhancement following SMM integration across devices with variable baseline tunneling currents. Independent Kelvin Probe Force Microscopy (KPFM) confirms that SMM channels alter the surface potential of the NiFe electrode [20], providing electrode-level validation of molecular influence. Finally, conceptual modeling links these effects to orbital-assisted tunneling and charge redistribution[19], offering a mechanistic framework for understanding the reproducibility of molecularly modified MIS junctions.\u003c/p\u003e\n\u003cp\u003eBy combining reproducible transport data, electrode-level characterization, and mechanistic interpretation, this study establishes the MIS\u0026ndash;SMM platform as a scalable testbed for molecular quantum materials. Although spin-selective transport remains to be confirmed, recent studies suggest that complementary magnetic and low-temperature techniques will be critical for capturing spin-dependent phenomena[21, 22]. Together, these results highlight a reproducible, scalable, and conceptually grounded strategy for advancing SMM-based molecular spintronics.\u003c/p\u003e"},{"header":"2.\tMethodology","content":"\u003cp\u003eNiFe/AlOx/p-Si metal\u0026ndash;insulator\u0026ndash;semiconductor (MIS) junctions were fabricated using standard photolithography and thin-film deposition (Fig. 1) [23]. \u0026nbsp;p-type Si (100) wafers (Fig.1a) were patterned via photolithography and etched in buffered HF solution to expose the semiconductor surface (Fig.1b). A 2 nm AlOx layer was deposited by RF sputtering, using the AJA International sputtering machine (Fig. 1c), followed by a ~15 nm NiFe top electrode deposited under Argon \u0026nbsp; plasma. Liftoff was performed in Micro posit 1165 solution, yielding cross-junction devices with exposed sidewalls (Fig.1d).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCurrent\u0026ndash;voltage (I\u0026ndash;V) characteristics were recorded on a micromanipulator probe station using a Keithley 6430 Sub-Femtoampere Remote Source Meter. Baseline I\u0026ndash;V curves were obtained for MIS junctions prior to molecular attachment, with tunneling behavior interpreted using Brinkman\u0026rsquo;s model\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLipoic acid\u0026ndash;functionalized Mn₆ SMMs were attached by immersing devices in a 0.1 mM ethanol solution for ~2 minutes while applying alternating \u0026plusmn;0.2 V bias to assist electrophoretic alignment, consistent with prior molecular junction studies that employed sub-millimolar concentrations to balance surface coverage and reproducibility [23-25]. Control studies, consistent with our prior demonstrations of molecular coupling effects in spintronic junctions [26], confirmed that only sidewall-bridged molecules contributed to transport, while surface-adsorbed species had negligible effect. The robustness of thiol/disulfide chemistry for electrode functionalization has also been well established in self-assembled monolayer studies [27].\u003c/p\u003e\n\u003cp\u003eKelvin Probe Force Microscopy (KPFM) measurements were performed on a NaioFlex AFM system to map electrode surface potentials before and after molecular bridging [28]. I\u0026ndash;V data were fitted using Brinkman\u0026rsquo;s tunneling model and the diode transport equation to extract barrier thickness, barrier height, and ideality factors. Solvent and interfacial effects were interpreted within the framework of prior studies of molecular environments [29]. These fabrication and characterization steps established the baseline necessary to evaluate the reproducibility and electrode-level impact of SMM integration.\u003c/p\u003e"},{"header":"3.\tResults and Discussion","content":"\u003cp\u003eCurrent\u0026ndash;voltage (I\u0026ndash;V) measurements of NiFe/AlOx/p-Si junctions revealed significant modulation after SMM integration. Baseline MIS devices showed variability in tunneling current due to differences in AlOx barrier quality, as expected from fabrication tolerances. Figures 2a\u0026ndash;e show representative I\u0026ndash;V curves for five junctions (J1\u0026ndash;J5). While the bare devices exhibited diverse current levels, after SMM bridging, all junctions displayed remarkably consistent transport behavior.\u003c/p\u003e\n\u003cp\u003eThis reproducibility was further validated by averaging transport characteristics across the five junctions (Figure 2f). The standard deviation in current decreased significantly after SMM attachment, confirming that molecular bridging yields uniform transport modulation independent of initial device variability. These findings demonstrate that SMMs establish stable and reproducible transport channels across multiple devices, strengthening the case for their integration into scalable device architectures.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo complement the electrical transport measurements, we performed Kelvin Probe Force Microscopy (KPFM) to map the surface potential before and after SMM attachment. As shown in Figure 3a, the pristine MIS device exhibited modest potential differences between NiFe, AlOx, and p-Si regions. After SMM integration (Figure 3b), a pronounced rise in NiFe electrode surface potential was observed. A line scan across the junction (Figure 3c) quantified this increase at approximately 0.4 V.\u003c/p\u003e\n\u003cp\u003eThe localized shift was most prominent at the junction region, consistent with SMM bridging at the exposed sidewalls. Importantly, the p-Si electrode potential remained largely unchanged, confirming that the modification arises from SMM\u0026ndash;NiFe coupling rather than substrate effects. This independent surface-potential evidence reinforces the transport data and rules out alternative explanations such as oxide defects.\u003c/p\u003e\n\u003cp\u003eThese findings suggest that SMM channels not only act as additional tunneling pathways but also alter the interfacial properties of NiFe. To better interpret the transport reproducibility and the observed ~0.4 V shift in surface potential, we developed a conceptual mechanism as illustrated in Figure 4. Although the present measurements were conducted at room temperature and do not capture spin-selective transport directly, the observed electrode-level modulation establishes a platform that can be extended with complementary techniques such as SQUID magnetometry, EPR spectroscopy, and low-temperature magneto-transport. By focusing on reproducibility and scalability while acknowledging the need for direct magnetic evidence, this study positions the MIS\u0026ndash;SMM platform as both a practical molecular testbed and a steppingstone toward spintronic device applications\u003c/p\u003e\n\u003cp\u003eTo rationalize these experimental observations, we propose a conceptual mechanism that highlights the role of SMM channels in MIS transport modulation (Figure 4).\u003c/p\u003e\n\u003cp\u003eIn the pristine NiFe/AlOx/p-Si structure (Figure 4a), electron conduction is dominated by tunneling through the AlOx barrier, with effective barrier properties varying due to fabrication tolerances. This variability explains the device-to-device differences in baseline I\u0026ndash;V curves.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAfter SMM functionalization (Figure 4b), robust disulfide anchoring enables molecular bridging between NiFe and p-Si. These molecules introduce orbital-assisted tunneling pathways via their LUMO levels, lowering the effective barrier height and increasing the local density of states (DOS) at the interface. As a result, electrons hop into SMM orbitals and tunnel through, producing enhanced and reproducible current across devices.\u003c/p\u003e\n\u003cp\u003eCharge redistribution at the NiFe/SMM interface further modifies the electrode surface potential, consistent with the ~0.4 V increase detected by KPFM. Together, these complementary effects provide a mechanistic explanation for both the reproducible transport enhancement and the electrode-level modification observed after SMM integration.\u003c/p\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eWe have demonstrated that sidewall bridging of lipoic acid\u0026ndash;functionalized Mn₆ SMMs transforms NiFe/AlOx/p-Si MIS junctions into reproducible molecular tunneling devices. Despite baseline variability in AlOx tunneling responses, molecular integration produced convergent I\u0026ndash;V characteristics across multiple devices, confirming that SMM channels dominate transport behavior. Kelvin Probe Force Microscopy revealed a ~0.4 V shift in NiFe surface potential after molecular attachment, while Brinkman model analysis verified uniform barrier parameters, reinforcing the robustness of the molecular effect. Together, these results establish reproducibility and scalability as defining features of the MIS\u0026ndash;SMM platform. Although direct spin-selective transport was not obtained here, the reproducibility of device-level modulation and electrode sensitivity demonstrated by KPFM position this architecture as a practical molecular testbed and a foundation for future spintronic applications.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFuture studies employing low-temperature magneto-transport, SQUID magnetometry, and EPR spectroscopy will be critical to directly probe spin-dependent phenomena and further advance the spintronic potential of MIS\u0026ndash;SMM systems.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe gratefully acknowledge the funding support from the National Science Foundation-CREST Award (Contract # HRD-1914751), NSF-MRI grant 1920097, Department of Energy/National Nuclear Security Agency (DE-FOA-0003945), and NASA MURP grant (80NSSC19M0196), at the Center for Nanotechnology Research and Education (CNRE), University of the District of Columbia. Thanks to Prof. Pawan Tyagi for mentorship and scientific guidance, Dr. Jos\u0026eacute; Mart\u0026iacute;nez-Lillo and Dr. Carlos Rojas-Dotti at the University of Valencia (ICMol) for providing Single-Molecule Magnet samples and valuable discussions, and Mr. Hayden Brown for technical assistance with thin-film deposition and cleanroom operations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is 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\u003eFunding Declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was supported by the National Science Foundation-CREST Award (Contract # HRD-1914751), NSF-MRI grant 1920097, Department of Energy/National Nuclear Security Agency (DE-FOA-0003945), and NASA MURP grant (80NSSC19M0196). The funding bodies had no role in the design of the study; in the collection, analysis, or interpretation of data; or in the writing of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBogani, L. and W. 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Mart\u0026iacute;nez-Lillo, \u003cem\u003eThioester-functionalised and oxime-based hexametallic manganese (III) single-molecule magnets.\u003c/em\u003e RSC Advances, 2017. \u003cstrong\u003e7\u003c/strong\u003e(77): p. 48841-48847.\u003c/li\u003e\n\u003cli\u003eOrts-Arroyo, M., et al., \u003cem\u003eLipoic Acid-Functionalized Hexanuclear Manganese(III) Nanomagnets Suitable for Surface Grafting.\u003c/em\u003e International Journal of Molecular Sciences, 2023. \u003cstrong\u003e24\u003c/strong\u003e(10): p. 8645.\u003c/li\u003e\n\u003cli\u003eTyagi, P., et al., \u003cem\u003eMolecular Electrodes At The Exposed Edge Of Metal/Insulator/Metal Trilayer Structures.\u003c/em\u003e Journal of the American Chemical Society, 2007. \u003cstrong\u003e129\u003c/strong\u003e(16): p. 4929-4938.\u003c/li\u003e\n\u003cli\u003eTyagi, P. and C. Riso, \u003cem\u003eMagnetic force microscopy revealing long range molecule impact on magnetic tunnel junction based molecular spintronics devices.\u003c/em\u003e Organic Electronics, 2019. \u003cstrong\u003e75\u003c/strong\u003e: p. 105421.\u003c/li\u003e\n\u003cli\u003eBarra, A.L. and et al., \u003cem\u003eNew single-molecule magnets by site-specific substitution: Incorporation of \u0026quot;Alligator clips\u0026quot; into Fe-4 complexes.\u003c/em\u003e European Journal of Inorganic Chemistry, 2007(26): p. 4145-4152.\u003c/li\u003e\n\u003cli\u003eSavadkoohi, M., et al., \u003cem\u003eSpin Solar Cell Phenomenon on a Single-Molecule Magnet (SMM) Impacted CoFeB-Based Magnetic Tunnel Junctions.\u003c/em\u003e ACS Applied Electronic Materials, 2023. \u003cstrong\u003e5\u003c/strong\u003e(6): p. 3333-3339.\u003c/li\u003e\n\u003cli\u003eMutunga, E. and et al., \u003cem\u003eMagnetic molecules lose identity when connected to different combinations of magnetic metal electrodes in MTJ-based molecular spintronics devices.\u003c/em\u003e Scientific Reports, 2023. \u003cstrong\u003e13\u003c/strong\u003e: p. 17128.\u003c/li\u003e\n\u003cli\u003eSavadkoohi, M. and et al., \u003cem\u003eIncreasing ferromagnet electrode thickness prevented molecular coupling producing room temperature stable current suppression.\u003c/em\u003e Journal of Applied Physics, 2022. \u003cstrong\u003e131\u003c/strong\u003e: p. 013901.\u003c/li\u003e\n\u003cli\u003eWu, X. and J. Davis, \u003cem\u003eSurface Potential Measurement Using KPFM.\u003c/em\u003e Journal of Applied Physics, 2020. \u003cstrong\u003e128\u003c/strong\u003e(9): p. 091101.\u003c/li\u003e\n\u003cli\u003eBrinkman, W.F., R.C. Dynes, and J.M. Rowell, \u003cem\u003eTunneling conductance of asymmetrical barriers.\u003c/em\u003e Journal of Applied Physics, 1970. \u003cstrong\u003e41\u003c/strong\u003e(5): p. 1915-1921.\u003c/li\u003e\n\u003cli\u003eXu, L. and et al., \u003cem\u003eA review on footsteps of a revolution in electronics: Spin memristors.\u003c/em\u003e Advanced Materials, 2025. \u003cstrong\u003e37\u003c/strong\u003e: p. 2500116.\u003c/li\u003e\n\u003cli\u003eSavadkoohi, M. and et al., \u003cem\u003eSingle-Molecule Magnet\u0026rsquo;s (SMM) effects on spin-dependent transport in antiferromagnet-based MTJ molecular spintronic devices.\u003c/em\u003e AIP Advances, 2025. \u003cstrong\u003e15\u003c/strong\u003e(3): p. 035035.\u003c/li\u003e\n\u003cli\u003eSankhi, S. and P. Tyagi, \u003cem\u003eMass-Scale Molecular Spintronics Devices Using Liftoff-Exposed Side Edges of Magnetic Tunnel Junctions.\u003c/em\u003e RSC Advances, 2020. \u003cstrong\u003e10\u003c/strong\u003e: p. 13006-13015.\u003c/li\u003e\n\u003cli\u003ePark, J., et al., \u003cem\u003eCoulomb Blockade and the Kondo Effect in Single-Atom Transistors.\u003c/em\u003e Nature, 2002. \u003cstrong\u003e417\u003c/strong\u003e: p. 722-725.\u003c/li\u003e\n\u003cli\u003eHeersche, H.B., et al., \u003cem\u003eElectrical Detection of Single-Molecule Magnetic Hysteresis.\u003c/em\u003e Physical Review Letters, 2006. \u003cstrong\u003e96\u003c/strong\u003e: p. 206801.\u003c/li\u003e\n\u003cli\u003eTyagi, P., et al., \u003cem\u003eIntra-Molecular Coupling within Double-Segmented Molecules Impacting Magnetic Tunnel Junction-Based Molecular Spintronics Devices.\u003c/em\u003e MRS Communications, 2024. \u003cstrong\u003e14\u003c/strong\u003e: p. 103-113.\u003c/li\u003e\n\u003cli\u003eLove, J.C., et al., \u003cem\u003eSelf-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology.\u003c/em\u003e Chemical Reviews, 2005. \u003cstrong\u003e105\u003c/strong\u003e: p. 1103-1170.\u003c/li\u003e\n\u003cli\u003eMelitz, W., et al., \u003cem\u003eKelvin Probe Force Microscopy and Its Application.\u003c/em\u003e Surface Science Reports, 2011. \u003cstrong\u003e66\u003c/strong\u003e: p. 1-27.\u003c/li\u003e\n\u003cli\u003eReichardt, C. and T. Welton, \u003cem\u003eSolvents and Solvent Effects in Organic Chemistry, 4th ed\u003c/em\u003e. 2011, Weinheim: Wiley-VCH.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7821044/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7821044/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSingle-Molecule Magnets (SMMs) are promising for molecular spintronics owing to their quantum properties; however, reproducible integration into devices has remained challenging due to limitations of break-junction and gold-based systems. This study introduces a scalable NiFe/AlOx/p-Si Metal–Insulator–Semiconductor (MIS) platform that enables reliable sidewall bridging of lipoic acid–functionalized Mn₆ SMMs through disulfide linkages. Despite fabrication-related variability in pristine MIS junctions, molecular integration produced convergent tunneling characteristics across multiple devices, as confirmed by standard deviation analysis, thus addressing reproducibility issues common in molecular systems.\u003c/p\u003e\n\u003cp\u003eKelvin Probe Force Microscopy (KPFM) revealed an approximately 0.4 V increase in NiFe surface potential following SMM attachment, providing electrode-level evidence of molecular influence. Conceptual modeling suggests two cooperative mechanisms: (i) orbital-assisted tunneling that reduces effective barrier height and enhances interfacial density of states, and (ii) charge redistribution at the NiFe/SMM interface, resulting in band flattening and surface potential rise. These mechanisms collectively account for the reproducibility and interfacial modifications observed experimentally.\u003c/p\u003e\n\u003cp\u003eAlthough spin-selective transport awaits direct confirmation, the demonstrated reproducibility and scalability establish this MIS–SMM architecture as a robust testbed for molecular integration and a viable route toward spintronic device applications. The study provides immediate relevance for molecular electronics and defines a foundation for advanced investigations using complementary low-temperature and magnetic characterization methods such as SQUID magnetometry, EPR spectroscopy, and magneto-transport.\u003c/p\u003e","manuscriptTitle":"Single-Molecule Magnet Bridging Along Exposed Sidewalls of Metal–Insulator–Semiconductor Diodes for Molecular Transport Studies","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-29 14:43:15","doi":"10.21203/rs.3.rs-7821044/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-27T10:46:45+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-23T19:23:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"118673735518074971290524846907291216166","date":"2026-01-15T14:57:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-07T11:42:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"73450836227800270743437758169888045261","date":"2026-01-05T12:03:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-15T12:40:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-15T12:34:26+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-15T11:43:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-14T21:43:16+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-10-14T21:40:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cae8d3b1-fe5b-4522-bf83-785036431463","owner":[],"postedDate":"October 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":56866070,"name":"Physical sciences/Materials science"},{"id":56866071,"name":"Physical sciences/Nanoscience and technology"},{"id":56866072,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-04-24T05:10:16+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-29 14:43:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7821044","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7821044","identity":"rs-7821044","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}