Optical Properties of Cr Thin Films as Substrates for Microalgae Detection Using Spectroscopic Ellipsometry based Sensor

Optical Properties of Cr Thin Films as Substrates for Microalgae Detection Using Spectroscopic Ellipsometry based Sensor | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Optical Properties of Cr Thin Films as Substrates for Microalgae Detection Using Spectroscopic Ellipsometry based Sensor Asmida Herawati, Riza Ariyani Nur Khasanah, Iman Santoso, Edi Suharyadi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5873205/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 Developing sensitive and reliable sensors for detecting microalgae is vital for various environmental and industrial applications. This study investigates the potential of chromium (Cr) thin films as substrates in spectroscopic ellipsometry (SE)-based sensors. Optical properties of Cr thin films (20–75 nm) were characterized using SE, showing a strong thickness dependence that directly impacts their suitability for sensing technologies. For 75 nm Cr thin films, the optical constants n and k closely align with those of bulk Cr, resulting in high reflectance, low absorption, and stable performance across a broad light spectrum, making 75 nm film particularly well-suited for multi-wavelength sensing applications. In contrast, as the thickness decreases, quantum confinement effects become increasingly pronounced, particularly at 30 nm and 20 nm. This leads to modified optical responses, such as increased n and k particularly at specific photon energy ranges, due to enhanced electron-photon interactions. The tunable optical properties of Cr thin films make them adaptable for applications requiring customized responses. Optimal conditions for microalgae detection were identified with a Cr thin film thickness of 75 nm, and photon energy range of 2.65‒3.30 eV. This was confirmed by a significant change in the ellipsometry parameter Δ (40.63°), indicating high sensitivity under these parameters. These findings pave the way for the development of highly sensitive and specific SE-based sensors using Cr thin films as substrates, offering promising advancements in the detection of microalgae for environmental and industrial applications. Full Text 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. 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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-5873205","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":405149588,"identity":"4f6afd5c-2281-4858-889b-021a32d28230","order_by":0,"name":"Asmida Herawati","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYJCCAwkGNnIGDIwNYB4bQwIRWj5UpBmTpoVxxpnDiRsQfAJa+PtPJx7mbWNO3y59uO0Bwy8bBj52AlokbuRuAGphy93Zl9huwNiXxsDG84CAq27wgrTw5G44w9gmwdhzmIFNgoAt8ufPgrRIpBsQrcXgQO6GgzPOGCSAtTD8IEKLIdAvwEBOMNzZA9SS2JDGQ9AvcufPbv6QYPBf3pyH/ZnEhz82cvLtBGxBBYltDDykqAeBP6RqGAWjYBSMgpEAABbFRqERoYENAAAAAElFTkSuQmCC","orcid":"","institution":"National Research and Innovation Agency (BRIN)","correspondingAuthor":true,"prefix":"","firstName":"Asmida","middleName":"","lastName":"Herawati","suffix":""},{"id":405149589,"identity":"c20e4890-b064-4b65-8c9f-3a2767e2dd23","order_by":1,"name":"Riza Ariyani Nur Khasanah","email":"","orcid":"","institution":"Universitas Negeri Yogyakarta","correspondingAuthor":false,"prefix":"","firstName":"Riza","middleName":"Ariyani Nur","lastName":"Khasanah","suffix":""},{"id":405149590,"identity":"515de4f0-19b3-470b-abe3-f7e39b38de4f","order_by":2,"name":"Iman Santoso","email":"","orcid":"","institution":"Gadjah Mada University","correspondingAuthor":false,"prefix":"","firstName":"Iman","middleName":"","lastName":"Santoso","suffix":""},{"id":405149591,"identity":"e554dc51-1bd4-4572-b01d-f2addbe163ec","order_by":3,"name":"Edi Suharyadi","email":"","orcid":"","institution":"Gadjah Mada University","correspondingAuthor":false,"prefix":"","firstName":"Edi","middleName":"","lastName":"Suharyadi","suffix":""}],"badges":[],"createdAt":"2025-01-21 11:38:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5873205/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5873205/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78397275,"identity":"2541cbee-cef6-46ee-acc7-456fb4d297d7","added_by":"auto","created_at":"2025-03-12 21:31:26","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":654137,"visible":true,"origin":"","legend":"","description":"","filename":"OpticalPropertiesofCrThinFilmsasSubstratesforMicroalgaeDetectionusingSpectroscopicEllipsometrybasedSensor.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5873205/v1_covered_f29324f1-8e96-4bf4-9887-4bdc7e61568b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Optical Properties of Cr Thin Films as Substrates for Microalgae Detection Using Spectroscopic Ellipsometry based Sensor","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"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":"","lastPublishedDoi":"10.21203/rs.3.rs-5873205/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5873205/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDeveloping sensitive and reliable sensors for detecting microalgae is vital for various environmental and industrial applications. This study investigates the potential of chromium (Cr) thin films as substrates in spectroscopic ellipsometry (SE)-based sensors. Optical properties of Cr thin films (20\u0026ndash;75 nm) were characterized using SE, showing a strong thickness dependence that directly impacts their suitability for sensing technologies. For 75 nm Cr thin films, the optical constants \u003cem\u003en\u003c/em\u003e and \u003cem\u003ek\u003c/em\u003e closely align with those of bulk Cr, resulting in high reflectance, low absorption, and stable performance across a broad light spectrum, making 75 nm film particularly well-suited for multi-wavelength sensing applications. In contrast, as the thickness decreases, quantum confinement effects become increasingly pronounced, particularly at 30 nm and 20 nm. This leads to modified optical responses, such as increased \u003cem\u003en\u003c/em\u003e and \u003cem\u003ek\u003c/em\u003e particularly at specific photon energy ranges, due to enhanced electron-photon interactions. The tunable optical properties of Cr thin films make them adaptable for applications requiring customized responses. Optimal conditions for microalgae detection were identified with a Cr thin film thickness of 75 nm, and photon energy range of 2.65‒3.30 eV. This was confirmed by a significant change in the ellipsometry parameter Δ (40.63\u0026deg;), indicating high sensitivity under these parameters. These findings pave the way for the development of highly sensitive and specific SE-based sensors using Cr thin films as substrates, offering promising advancements in the detection of microalgae for environmental and industrial applications.\u003c/p\u003e","manuscriptTitle":"Optical Properties of Cr Thin Films as Substrates for Microalgae Detection Using Spectroscopic Ellipsometry based Sensor","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-23 05:43:17","doi":"10.21203/rs.3.rs-5873205/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":"7ca90cf3-dcc2-428e-b568-65c90a2e3522","owner":[],"postedDate":"January 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-03-12T21:23:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-23 05:43:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5873205","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5873205","identity":"rs-5873205","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}