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Rajarajan, Sundaravadivel 2015-07-22T22:17:04Z 2015-07-22T22:17:04Z 2015-05 2015-04-20 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. 2015-5 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 application/pdf http://hdl.handle.net/2142/78417 en Copyright 2015 Sundaravadivel Rajarajan 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 Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy text text Electrical & Computer Engineering Electrical & Computer Engineering University of Illinois at Urbana-Champaign Thesis M.S.