{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/113342"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/113342","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum","abstract":"This thesis demonstrates the studies of 1T-TaS2, a member of the transition metal dichalcogenides (TMDCs) family, and wet-chemically synthesized zigzag-shape graphene nanoribbons (GNRs) on hydrogen passivated silicon substrate through scanning tunneling microscopy (STM). Dry contact transfer allows unperturbed transfer and exfoliation of desired two-dimensional (2D) layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer 1T-TaS2 under room temperature. Exploration of existence of charge density waves (CDWs) in monolayer 1T-TaS2 is in progress. Past work on surface modification of another TMDC material, MoS2, using STM has shown successful removal of desired atoms to form letters on the sample surface. Hypothesis of modifying monolayer 1T-TaS2 surface structure using similar technique may result in intriguing mechanical or electronic properties. Detailed STM imaging and STS measurements of wet chemically synthesized zigzag shape GNRs exhibit an atomic structure matching the expected molecular formula, and alternating bandgap energies of 0.4 eV and 2.68 eV, presumably due to the alternating armchair and zigzag edge terminations.","abstract_html":"This thesis demonstrates the studies of 1T-TaS2, a member of the transition metal dichalcogenides (TMDCs) family, and wet-chemically synthesized zigzag-shape graphene nanoribbons (GNRs) on hydrogen passivated silicon substrate through scanning tunneling microscopy (STM). Dry contact transfer allows unperturbed transfer and exfoliation of desired two-dimensional (2D) layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer 1T-TaS2 under room temperature. Exploration of existence of charge density waves (CDWs) in monolayer 1T-TaS2 is in progress. Past work on surface modification of another TMDC material, MoS2, using STM has shown successful removal of desired atoms to form letters on the sample surface. Hypothesis of modifying monolayer 1T-TaS2 surface structure using similar technique may result in intriguing mechanical or electronic properties. Detailed STM imaging and STS measurements of wet chemically synthesized zigzag shape GNRs exhibit an atomic structure matching the expected molecular formula, and alternating bandgap energies of 0.4 eV and 2.68 eV, presumably due to the alternating armchair and zigzag edge terminations.","abstract_has_math":false,"creators":["Wang, Hanfei"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Lyding, Joseph"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-01-12T22:56:14Z","date_published":"2022-01-12T22:56:14Z","updated_at":"2026-07-22T22:24:53Z","subjects":["Scanning tunneling microscopy","2D materials"],"languages":["en"],"rights":["Copyright 2021 Hanfei Wang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/113342","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lyding, Joseph"]},{"key":"dc:creator","label":"Author","values":["Wang, Hanfei"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-01-12T22:56:14Z","2024-01-12T22:56:20Z","2021-07-21","2021-08"]},{"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":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["Scanning tunneling microscopy","2D materials"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Hanfei Wang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/113342"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["This thesis demonstrates the studies of 1T-TaS2, a member of the transition metal dichalcogenides (TMDCs) family, and wet-chemically synthesized zigzag-shape graphene nanoribbons (GNRs) on hydrogen passivated silicon substrate through scanning tunneling microscopy (STM). Dry contact transfer allows unperturbed transfer and exfoliation of desired two-dimensional (2D) layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer 1T-TaS2 under room temperature. Exploration of existence of charge density waves (CDWs) in monolayer 1T-TaS2 is in progress. Past work on surface modification of another TMDC material, MoS2, using STM has shown successful removal of desired atoms to form letters on the sample surface. Hypothesis of modifying monolayer 1T-TaS2 surface structure using similar technique may result in intriguing mechanical or electronic properties. Detailed STM imaging and STS measurements of wet chemically synthesized zigzag shape GNRs exhibit an atomic structure matching the expected molecular formula, and alternating bandgap energies of 0.4 eV and 2.68 eV, presumably due to the alternating armchair and zigzag edge terminations.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-08-01","The student, Hanfei Wang, accepted the attached license on 2021-07-21 at 00:27.","The student, Hanfei Wang, submitted this Thesis for approval on 2021-07-21 at 00:32.","This Thesis was approved for publication on 2021-07-21 at 10:47.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17039 on 2022-01-12 at 13:05:22","Made available in DSpace on 2022-01-12T22:56:14Z (GMT). No. of bitstreams: 2 WANG-THESIS-2021.pdf: 26187479 bytes, checksum: e1ec8e78aa042b9d5b1fb147792c5a4d (MD5) LICENSE.txt: 4208 bytes, checksum: 5b74a03150e1770cbe68d639e873d507 (MD5) Previous issue date: 2021-07-21","Embargo set by: Seth Robbins for item 121271 Lift date: 2024-01-12T22:56:20Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum"]}]}],"canonical_facts":{"dc:contributor":["Lyding, Joseph"],"dc:creator":["Wang, Hanfei"],"dc:date":["2022-01-12T22:56:14Z","2024-01-12T22:56:20Z","2021-07-21","2021-08"],"dc:description":["This thesis demonstrates the studies of 1T-TaS2, a member of the transition metal dichalcogenides (TMDCs) family, and wet-chemically synthesized zigzag-shape graphene nanoribbons (GNRs) on hydrogen passivated silicon substrate through scanning tunneling microscopy (STM). Dry contact transfer allows unperturbed transfer and exfoliation of desired two-dimensional (2D) layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer 1T-TaS2 under room temperature. Exploration of existence of charge density waves (CDWs) in monolayer 1T-TaS2 is in progress. Past work on surface modification of another TMDC material, MoS2, using STM has shown successful removal of desired atoms to form letters on the sample surface. Hypothesis of modifying monolayer 1T-TaS2 surface structure using similar technique may result in intriguing mechanical or electronic properties. Detailed STM imaging and STS measurements of wet chemically synthesized zigzag shape GNRs exhibit an atomic structure matching the expected molecular formula, and alternating bandgap energies of 0.4 eV and 2.68 eV, presumably due to the alternating armchair and zigzag edge terminations.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-08-01","The student, Hanfei Wang, accepted the attached license on 2021-07-21 at 00:27.","The student, Hanfei Wang, submitted this Thesis for approval on 2021-07-21 at 00:32.","This Thesis was approved for publication on 2021-07-21 at 10:47.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17039 on 2022-01-12 at 13:05:22","Made available in DSpace on 2022-01-12T22:56:14Z (GMT). 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