1 research outputs found
Influence of Gas Adsorption and Gold Nanoparticles on the Electrical Properties of CVD-Grown MoS<sub>2</sub> Thin Films
Molybdenum
disulfide (MoS<sub>2</sub>) has increasingly attracted attention from
researchers and is now one of the most intensively explored atomic-layered
two-dimensional semiconductors. Control of the carrier concentration
and doping type of MoS<sub>2</sub> is crucial for its application
in electronic and optoelectronic devices. Because the MoS<sub>2</sub> layers are atomically thin, their transport characteristics may
be very sensitive to ambient gas adsorption and the resulting charge
transfer. We investigated the influence of the ambient gas (N<sub>2</sub>, H<sub>2</sub>/N<sub>2</sub>, and O<sub>2</sub>) choice on
the resistance (<i>R</i>) and surface work function (WF)
of trilayer MoS<sub>2</sub> thin films grown via chemical vapor deposition.
We also studied the electrical properties of gold (Au)-nanoparticle
(NP)-coated MoS<sub>2</sub> thin films; their <i>R</i> value
was found to be 2 orders of magnitude smaller than that for bare samples.
While the WF largely varied for each gas, <i>R</i> was almost
invariant for both the bare and Au-NP-coated samples regardless of
which gas was used. Temperature-dependent transport suggests that
variable range hopping is the dominant mechanism for electrical conduction
for bare and Au-NP-coated MoS<sub>2</sub> thin films. The charges
transferred from the gas adsorbates might be insufficient to induce
measurable <i>R</i> change and/or be trapped in the defect
states. The smaller WF and larger localization length of the Au-NP-coated
sample, compared with the bare sample, suggest that more carriers
and less defects enhanced conduction in MoS<sub>2</sub>