Open AccessA Method Toward Fabricating Semiconducting 3R-NbS2 Ultrathin Films
Author(s) -
Jatis Kumar Dash,
Liang Chen,
Peter H. Dinolfo,
TohMing Lu,
G.-C. Wang
Publication year - 2015
Publication title -
the journal of physical chemistry c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.5b04057
Subject(s) - raman spectroscopy , materials science , x ray photoelectron spectroscopy , ultraviolet , chemical vapor deposition , thin film , stoichiometry , analytical chemistry (journal) , sputtering , metal , diffraction , infrared , oxide , optoelectronics , chemical engineering , nanotechnology , optics , chemistry , metallurgy , physics , chromatography , engineering
Ultrathin NbS2 films were synthesized from sputter-deposited ultrathin Nb films on SiO2/Si and quartz substrates at 850 °C under sulfur vapor pressure. The structure and surface composition of the synthesized films were characterized by grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. The films have rhombohedral 3R-NbS2 structure and are nearly stoichiometric. The optical bandgaps of ultrathin NbS2 samples were determined from ultraviolet–visible-near–infrared spectrometry to be in the range of ∼0.43 to ∼0.90 eV and indirect. This implies that the ultrathin NbS2 film is semiconducting and differs from the metallic nature of bulk NbS2. The Raman shifts show distinct Raman active modes that depend on film thickness. The simple growth method developed can be applied to other TMDCs in which the metal has a high oxide heat of formation.
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