Graphene–germanium-on-insulator (GGOI) Schottky diode photodetector

Graphene–germanium-on-insulator (GGOI) Schottky diode 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 Graphene–germanium-on-insulator (GGOI) Schottky diode photodetector Loïc Rayneau, Mansour Aouassa, Adonis Takala, Olivier Gourhant, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8928340/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract We report a hybrid graphene/Ge-on-insulator (GGOI) photodetector fabricated from an ultrathin GOI template obtained by thermal condensation of Ge in a SiGe/UT-SOI stack, using a low-cost, CMOS-compatible approach. A thick Ge layer (~ 800 nm) is then deposited by LPCVD to form a high-quality GOI absorber. A CVD graphene electrode was subsequently transferred onto the GOI surface, previously covered with an ultrathin GeOₓ interfacial layer formed by rapid thermal oxidation (RTO) to promote graphene adhesion, as confirmed by HR-TEM analyses. Compared to the AuPd/GOI reference structure, the AuPd/G/GOI device exhibits (i) a significantly modified capacitive response, attributed to the superposition of the geometric capacitance of the GOI stack and the quantum capacitance of graphene, and (ii) a markedly enhanced rectification. Analysis of transport under high field conditions (|V| ≥ 6 V), based on Schottky, Poole–Frenkel, and Fowler–Nordheim representations, shows that conduction remains dominated by barrier-controlled (Schottky-like) injection, consistent with an effective MIS contact governed by the GeOₓ layer, rather than by a Fowler–Nordheim tunnel. Graphene insertion promotes a more uniform electric-field distribution and reduces the influence of interface states, leading to improved carrier injection and collection. The extracted ideality factor and Schottky barrier height are n ≈ 1.3 and ϕB ≈ 0.68 eV, respectively. Under monochromatic illumination at 578 nm and moderate reverse polarization (− 2.5 V), the photodetector achieves a responsiveness of 0.446 A/W (EQE ≈ 95.6%) and a specific detectivity, limited by shot noise, of approximately 2.3 × 10¹⁰ Jones. Finally, the device exhibits a stable and reproducible response to pulsed optical excitation, even at low voltage (< 0.5 V), confirming its potential for low-power photodetection. Physical sciences/Energy science and technology Physical sciences/Materials science Physical sciences/Nanoscience and technology Physical sciences/Optics and photonics Physical sciences/Physics Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 07 May, 2026 Reviews received at journal 04 May, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers invited by journal 20 Apr, 2026 Editor assigned by journal 13 Mar, 2026 Submission checks completed at journal 06 Mar, 2026 First submitted to journal 20 Feb, 2026 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8928340","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":626429691,"identity":"6439df96-4b9f-45ac-929a-cee9f9ed06f8","order_by":0,"name":"Loïc Rayneau","email":"","orcid":"","institution":"Aix-Marseille University","correspondingAuthor":false,"prefix":"","firstName":"Loïc","middleName":"","lastName":"Rayneau","suffix":""},{"id":626429693,"identity":"0839f232-e088-464b-9616-562dc443d8c1","order_by":1,"name":"Mansour Aouassa","email":"","orcid":"","institution":"College of Science and Arts, Jouf 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A thick Ge layer (~\u0026thinsp;800 nm) is then deposited by LPCVD to form a high-quality GOI absorber. A CVD graphene electrode was subsequently transferred onto the GOI surface, previously covered with an ultrathin GeOₓ interfacial layer formed by rapid thermal oxidation (RTO) to promote graphene adhesion, as confirmed by HR-TEM analyses. Compared to the AuPd/GOI reference structure, the AuPd/G/GOI device exhibits (i) a significantly modified capacitive response, attributed to the superposition of the geometric capacitance of the GOI stack and the quantum capacitance of graphene, and (ii) a markedly enhanced rectification. Analysis of transport under high field conditions (|V| \u0026ge; 6 V), based on Schottky, Poole\u0026ndash;Frenkel, and Fowler\u0026ndash;Nordheim representations, shows that conduction remains dominated by barrier-controlled (Schottky-like) injection, consistent with an effective MIS contact governed by the GeOₓ layer, rather than by a Fowler\u0026ndash;Nordheim tunnel. Graphene insertion promotes a more uniform electric-field distribution and reduces the influence of interface states, leading to improved carrier injection and collection. The extracted ideality factor and Schottky barrier height are n\u0026thinsp;\u0026asymp;\u0026thinsp;1.3 and ϕB\u0026thinsp;\u0026asymp;\u0026thinsp;0.68 eV, respectively. Under monochromatic illumination at 578 nm and moderate reverse polarization (\u0026minus;\u0026thinsp;2.5 V), the photodetector achieves a responsiveness of 0.446 A/W (EQE\u0026thinsp;\u0026asymp;\u0026thinsp;95.6%) and a specific detectivity, limited by shot noise, of approximately 2.3 \u0026times; 10\u0026sup1;⁰ Jones. Finally, the device exhibits a stable and reproducible response to pulsed optical excitation, even at low voltage (\u0026lt;\u0026thinsp;0.5 V), confirming its potential for low-power photodetection.\u003c/p\u003e","manuscriptTitle":"Graphene–germanium-on-insulator (GGOI) Schottky diode photodetector","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-28 19:04:03","doi":"10.21203/rs.3.rs-8928340/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-08T02:38:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-05T02:21:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"251340115431000739209480554188611549681","date":"2026-04-20T15:02:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"95179072045233260201397130566743892951","date":"2026-04-20T12:25:54+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-20T09:08:51+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-13T12:16:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-06T08:01:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"npj 2D Materials and Applications","date":"2026-02-20T18:07:13+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-2d-materials-and-applications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"npj2dmaterials","sideBox":"Learn more about [npj 2D Materials and Applications](http://www.nature.com/npj2dmaterials/)","snPcode":"41699","submissionUrl":"https://submission.springernature.com/new-submission/41699/3","title":"npj 2D Materials and Applications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"db300df4-eec7-41d7-8066-a568db186dd7","owner":[],"postedDate":"April 28th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-08T02:38:15+00:00","index":16,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-05T02:21:52+00:00","index":15,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":66670599,"name":"Physical sciences/Energy science and technology"},{"id":66670600,"name":"Physical sciences/Materials science"},{"id":66670601,"name":"Physical sciences/Nanoscience and technology"},{"id":66670602,"name":"Physical sciences/Optics and photonics"},{"id":66670603,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-04-28T19:04:03+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-28 19:04:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8928340","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8928340","identity":"rs-8928340","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}