{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/78417"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/78417","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy","abstract":"Over the past decade, due to the increasing interest and urgency in finding an alternate material system for post-silicon logic and opto-electronic applications, staggering progress have been made in the study of low-dimensional materials. These low-dimensional materials not only help reduce transistor footprint and improve power and performance metrics, they also exhibit very peculiar electrical properties. A particular example is the existence of a charge density wave (CDW) in 1T-Tantalum (IV) Sulfide (1T-TaS2). A member of the transition metal dichalcogenide (TMDC) family, 1T-TaS2 exhibit a periodic modulation of electronic charge density. Unlike bulk semiconductor or metals, lattice distortion in this low-dimensional material creates non-uniform, wave-like electron densities. In this thesis, we have demonstrated two bulk material growth strategies for the synthesis of 1T-TaS2. We have successfully grown poly-crystalline 1T-TaS2 powder through a direct solid-solid reaction and single-crystals of 1T-TaS2 through Iodine-assisted chemical vapor transport (CVT). After a few growth setup revisions, the growth processes have given consistently high yields. Next, we performed an ultra-high vacuum scanning tunneling microscopy (UHV-STM) study of the grown poly-crystalline 1T-TaS2. The powder was deposited onto an atomically flat, H-passivated silicon substrate using dry contact transfer (DCT), an in-situ deposition technique developed by the Lyding group for clean, UHV-compatible transfer of nano-materials. We managed to directly observe room-temperature CDW on the deposited nano-flakes of 1T-TaS2. The periodicity of the CDW lat- tice correspond very closely to the expected sqrt(13) x sqrt(13) nearly commensurate room-temperature CDW phase.","abstract_html":"Over the past decade, due to the increasing interest and urgency in finding an alternate material system for post-silicon logic and opto-electronic applications, staggering progress have been made in the study of low-dimensional materials. These low-dimensional materials not only help reduce transistor footprint and improve power and performance metrics, they also exhibit very peculiar electrical properties. A particular example is the existence of a charge density wave (CDW) in 1T-Tantalum (IV) Sulfide (1T-TaS2). A member of the transition metal dichalcogenide (TMDC) family, 1T-TaS2 exhibit a periodic modulation of electronic charge density. Unlike bulk semiconductor or metals, lattice distortion in this low-dimensional material creates non-uniform, wave-like electron densities. In this thesis, we have demonstrated two bulk material growth strategies for the synthesis of 1T-TaS2. We have successfully grown poly-crystalline 1T-TaS2 powder through a direct solid-solid reaction and single-crystals of 1T-TaS2 through Iodine-assisted chemical vapor transport (CVT). After a few growth setup revisions, the growth processes have given consistently high yields. Next, we performed an ultra-high vacuum scanning tunneling microscopy (UHV-STM) study of the grown poly-crystalline 1T-TaS2. The powder was deposited onto an atomically flat, H-passivated silicon substrate using dry contact transfer (DCT), an in-situ deposition technique developed by the Lyding group for clean, UHV-compatible transfer of nano-materials. We managed to directly observe room-temperature CDW on the deposited nano-flakes of 1T-TaS2. The periodicity of the CDW lat- tice correspond very closely to the expected sqrt(13) x sqrt(13) nearly commensurate room-temperature CDW phase.","abstract_has_math":false,"creators":["Rajarajan, Sundaravadivel"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-07-22T22:17:04Z","date_published":"2015-07-22T22:17:04Z","updated_at":"2026-07-22T22:26:11Z","subjects":["Charge Density Wave","Transition Metal Dichalcogenides (TMDC)","1T-Tantalum (IV) Sulfide (1T-TaS2)","Tantalum Disulfide","Scanning Tunneling Microscope","Ultra-High Vacuum","2D Material","Chemical Vapor Transport"],"languages":["en"],"rights":["Copyright 2015 Sundaravadivel Rajarajan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/78417","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Rajarajan, Sundaravadivel"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-07-22T22:17:04Z","2015-05","2015-04-20","2015-5"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engineering"]},{"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":["Charge Density Wave","Transition Metal Dichalcogenides (TMDC)","1T-Tantalum (IV) Sulfide (1T-TaS2)","Tantalum Disulfide","Scanning Tunneling Microscope","Ultra-High Vacuum","2D Material","Chemical Vapor Transport"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2015 Sundaravadivel Rajarajan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/78417"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Over the past decade, due to the increasing interest and urgency in finding an alternate material system for post-silicon logic and opto-electronic applications, staggering progress have been made in the study of low-dimensional materials. These low-dimensional materials not only help reduce transistor footprint and improve power and performance metrics, they also exhibit very peculiar electrical properties. A particular example is the existence of a charge density wave (CDW) in 1T-Tantalum (IV) Sulfide (1T-TaS2). A member of the transition metal dichalcogenide (TMDC) family, 1T-TaS2 exhibit a periodic modulation of electronic charge density. Unlike bulk semiconductor or metals, lattice distortion in this low-dimensional material creates non-uniform, wave-like electron densities. In this thesis, we have demonstrated two bulk material growth strategies for the synthesis of 1T-TaS2. We have successfully grown poly-crystalline 1T-TaS2 powder through a direct solid-solid reaction and single-crystals of 1T-TaS2 through Iodine-assisted chemical vapor transport (CVT). After a few growth setup revisions, the growth processes have given consistently high yields. Next, we performed an ultra-high vacuum scanning tunneling microscopy (UHV-STM) study of the grown poly-crystalline 1T-TaS2. The powder was deposited onto an atomically flat, H-passivated silicon substrate using dry contact transfer (DCT), an in-situ deposition technique developed by the Lyding group for clean, UHV-compatible transfer of nano-materials. We managed to directly observe room-temperature CDW on the deposited nano-flakes of 1T-TaS2. The periodicity of the CDW lat- tice correspond very closely to the expected sqrt(13) x sqrt(13) nearly commensurate room-temperature CDW phase.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms","The student, Sundaravadivel Rajarajan, accepted the attached license on 2015-04-19 at 14:23.","The student, Sundaravadivel Rajarajan, submitted this Thesis for approval on 2015-04-19 at 14:55.","This Thesis was approved for publication on 2015-04-20 at 10:22.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7939 on 2015-07-22 at 10:32:44","Made available in DSpace on 2015-07-22T22:17:04Z (GMT). No. of bitstreams: 2 RAJARAJAN-THESIS-2015.pdf: 21298273 bytes, checksum: a18ba991ac7b69832700b9840e64265a (MD5) LICENSE.txt: 4221 bytes, checksum: 699ce9c840451d626ccfcc40116882f9 (MD5) Previous issue date: 2015-04-20"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy"]}]}],"canonical_facts":{"dc:creator":["Rajarajan, Sundaravadivel"],"dc:date":["2015-07-22T22:17:04Z","2015-05","2015-04-20","2015-5"],"dc:description":["Over the past decade, due to the increasing interest and urgency in finding an alternate material system for post-silicon logic and opto-electronic applications, staggering progress have been made in the study of low-dimensional materials. These low-dimensional materials not only help reduce transistor footprint and improve power and performance metrics, they also exhibit very peculiar electrical properties. A particular example is the existence of a charge density wave (CDW) in 1T-Tantalum (IV) Sulfide (1T-TaS2). A member of the transition metal dichalcogenide (TMDC) family, 1T-TaS2 exhibit a periodic modulation of electronic charge density. Unlike bulk semiconductor or metals, lattice distortion in this low-dimensional material creates non-uniform, wave-like electron densities. In this thesis, we have demonstrated two bulk material growth strategies for the synthesis of 1T-TaS2. We have successfully grown poly-crystalline 1T-TaS2 powder through a direct solid-solid reaction and single-crystals of 1T-TaS2 through Iodine-assisted chemical vapor transport (CVT). After a few growth setup revisions, the growth processes have given consistently high yields. Next, we performed an ultra-high vacuum scanning tunneling microscopy (UHV-STM) study of the grown poly-crystalline 1T-TaS2. The powder was deposited onto an atomically flat, H-passivated silicon substrate using dry contact transfer (DCT), an in-situ deposition technique developed by the Lyding group for clean, UHV-compatible transfer of nano-materials. We managed to directly observe room-temperature CDW on the deposited nano-flakes of 1T-TaS2. The periodicity of the CDW lat- tice correspond very closely to the expected sqrt(13) x sqrt(13) nearly commensurate room-temperature CDW phase.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms","The student, Sundaravadivel Rajarajan, accepted the attached license on 2015-04-19 at 14:23.","The student, Sundaravadivel Rajarajan, submitted this Thesis for approval on 2015-04-19 at 14:55.","This Thesis was approved for publication on 2015-04-20 at 10:22.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7939 on 2015-07-22 at 10:32:44","Made available in DSpace on 2015-07-22T22:17:04Z (GMT). No. of bitstreams: 2 RAJARAJAN-THESIS-2015.pdf: 21298273 bytes, checksum: a18ba991ac7b69832700b9840e64265a (MD5) LICENSE.txt: 4221 bytes, checksum: 699ce9c840451d626ccfcc40116882f9 (MD5) Previous issue date: 2015-04-20"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/78417"],"dc:language":["en"],"dc:rights":["Copyright 2015 Sundaravadivel Rajarajan"],"dc:subject":["Charge Density Wave","Transition Metal Dichalcogenides (TMDC)","1T-Tantalum (IV) Sulfide (1T-TaS2)","Tantalum Disulfide","Scanning Tunneling Microscope","Ultra-High Vacuum","2D Material","Chemical Vapor Transport"],"dc:title":["Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy"],"dc:type":["text"],"thesis:degree_discipline":["Electrical & Computer Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:11Z"}