{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/113892"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/113892","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"A study toward large-area low-defect nanosphere lithography","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms","abstract_has_math":false,"creators":["Grewal, Sartaj S"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Lyding, Joseph W","Murphy, Catherine J","Li, Xiuling","Chen, Qian","Fang, Kejie"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-04-29T21:34:45Z","date_published":"2022-04-29T21:34:45Z","updated_at":"2026-07-22T22:24:53Z","subjects":["Engineering"],"languages":["en","eng"],"rights":["Copyright 2021 Sartaj Grewal"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/113892","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lyding, Joseph W","Murphy, Catherine J","Li, Xiuling","Chen, Qian","Fang, Kejie"]},{"key":"dc:creator","label":"Author","values":["Grewal, Sartaj S"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-04-29T21:34:45Z","2021-12","2021-12-02"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Sartaj Grewal"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/113892"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms","The student, Sartaj Grewal, accepted the attached license on 2021-12-01 at 10:51.","The student, Sartaj Grewal, submitted this Dissertation for approval on 2021-12-01 at 11:11.","This Dissertation was approved for publication on 2021-12-02 at 10:40.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17332 on 2022-04-06 at 17:10:33","Made available in DSpace on 2022-04-29T21:34:45Z (GMT). No. of bitstreams: 3 GREWAL-DISSERTATION-2021.pdf: 15332161 bytes, checksum: e5ed8796edffc6573e6588b863511e27 (MD5) LICENSE.txt: 4210 bytes, checksum: 90dee2c690d03f3f86967c64d02ce98f (MD5) PROQUEST_LICENSE.txt: 4556 bytes, checksum: 52428b5ffa04db157908b332ba7a9133 (MD5) Previous issue date: 2021-12-02","Surface-enhanced Raman spectroscopy (SERS) is a powerful label-free molecular characterization technique that detects ultra-low analyte concentrations. The critical requirement for the SERS enhancement effect is the presence of large magnitude electromagnetic fields existing between small-gap nanoparticle dimers. Considerable research effort is devoted to developing uniform and high enhancement response from SERS-based sensors. The achievement of this aim using uncomplicated and low-cost methods remains an active challenge nonetheless. Nanosphere lithography (NSL) leverages the benefits of a self-assembled nanosphere mask to deliver spontaneous high-density patterning of triangular nanoparticles. The use of a two-step shadow evaporation method with NSL masks creates programmable gap nanoparticle dimers. However, reliable control over the dimer gap requires further study of the mask properties. This thesis aims to combine the shadow evaporation method with large-area single-crystalline nanosphere masks to create sub-10 nm gap nanoparticle dimer arrays. A novel dynamic self-assembly process for large-area quasi-single crystals of polymeric spheres is detailed. The addition of propylene glycol to the colloidal solution and low-velocity air and low-frequency acoustic external energy input unlocks the reliable fabrication of high-quality masks. The short-range and long-range defect density characterization identifies sphere polydispersity and evaporation-induced line defects as the primary causes of defect generation. Solvent treatment of the colloidal crystal reduces mean defect density by a factor of 5x with complete elimination of evaporation-induced line defects. The long-range orientation of the colloidal crystal is preferentially realigned to a single orientation using a hexagonal hydrophobic template. Nanoparticle arrays made from the improved masks demonstrate enhancement factors of 8.95 × 10^(6) and uniformities below 12%."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["A study toward large-area low-defect nanosphere lithography"]}]}],"canonical_facts":{"dc:contributor":["Lyding, Joseph W","Murphy, Catherine J","Li, Xiuling","Chen, Qian","Fang, Kejie"],"dc:creator":["Grewal, Sartaj S"],"dc:date":["2022-04-29T21:34:45Z","2021-12","2021-12-02"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms","The student, Sartaj Grewal, accepted the attached license on 2021-12-01 at 10:51.","The student, Sartaj Grewal, submitted this Dissertation for approval on 2021-12-01 at 11:11.","This Dissertation was approved for publication on 2021-12-02 at 10:40.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17332 on 2022-04-06 at 17:10:33","Made available in DSpace on 2022-04-29T21:34:45Z (GMT). No. of bitstreams: 3 GREWAL-DISSERTATION-2021.pdf: 15332161 bytes, checksum: e5ed8796edffc6573e6588b863511e27 (MD5) LICENSE.txt: 4210 bytes, checksum: 90dee2c690d03f3f86967c64d02ce98f (MD5) PROQUEST_LICENSE.txt: 4556 bytes, checksum: 52428b5ffa04db157908b332ba7a9133 (MD5) Previous issue date: 2021-12-02","Surface-enhanced Raman spectroscopy (SERS) is a powerful label-free molecular characterization technique that detects ultra-low analyte concentrations. The critical requirement for the SERS enhancement effect is the presence of large magnitude electromagnetic fields existing between small-gap nanoparticle dimers. Considerable research effort is devoted to developing uniform and high enhancement response from SERS-based sensors. The achievement of this aim using uncomplicated and low-cost methods remains an active challenge nonetheless. Nanosphere lithography (NSL) leverages the benefits of a self-assembled nanosphere mask to deliver spontaneous high-density patterning of triangular nanoparticles. The use of a two-step shadow evaporation method with NSL masks creates programmable gap nanoparticle dimers. However, reliable control over the dimer gap requires further study of the mask properties. This thesis aims to combine the shadow evaporation method with large-area single-crystalline nanosphere masks to create sub-10 nm gap nanoparticle dimer arrays. A novel dynamic self-assembly process for large-area quasi-single crystals of polymeric spheres is detailed. The addition of propylene glycol to the colloidal solution and low-velocity air and low-frequency acoustic external energy input unlocks the reliable fabrication of high-quality masks. The short-range and long-range defect density characterization identifies sphere polydispersity and evaporation-induced line defects as the primary causes of defect generation. Solvent treatment of the colloidal crystal reduces mean defect density by a factor of 5x with complete elimination of evaporation-induced line defects. The long-range orientation of the colloidal crystal is preferentially realigned to a single orientation using a hexagonal hydrophobic template. Nanoparticle arrays made from the improved masks demonstrate enhancement factors of 8.95 × 10^(6) and uniformities below 12%."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/113892"],"dc:language":["en","eng"],"dc:rights":["Copyright 2021 Sartaj Grewal"],"dc:subject":["Engineering"],"dc:title":["A study toward large-area low-defect nanosphere lithography"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:53Z"}