Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum
Wang, Hanfei
Loading…
Permalink
https://hdl.handle.net/2142/113342
Description
Title
Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum
Author(s)
Wang, Hanfei
Issue Date
2021-07-21
Director of Research (if dissertation) or Advisor (if thesis)
Lyding, Joseph
Department of Study
Electrical & Computer Eng
Discipline
Electrical & Computer Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
Scanning tunneling microscopy
2D materials
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.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
