title: Influence of Gas Adsorption and Gold Nanoparticles on the Electrical Properties of CVD-Grown MoS2 Thin Films.
abstract: Molybdenum disulfide (MoS2) 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 MoS2 is crucial for its application in electronic and optoelectronic devices. Because the MoS2 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 (N2, H2/N2, and O2) choice on the resistance (R) and surface work function (WF) of trilayer MoS2 thin films grown via chemical vapor deposition. We also studied the electrical properties of gold (Au)-nanoparticle (NP)-coated MoS2 thin films; their R value was found to be 2 orders of magnitude smaller than that for bare samples. While the WF largely varied for each gas, R 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 MoS2 thin films. The charges transferred from the gas adsorbates might be insufficient to induce measurable R 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 MoS2.
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 03760, Korea.
authors.forename: Yunae
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 03760, Korea.
authors.forename: Ahrum
authors.initials: A
authors.lastname: Sohn
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 03760, Korea.
authors.forename: Sujung
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Advanced Functional Thin Films, Korea Institute of Materials Science (KIMS) , Changwon 51508, Korea.|Department of Materials Science & Engineering, Inha University , Incheon 22212, Korea.
authors.forename: Myung Gwan
authors.initials: MG
authors.lastname: Hahm
authors.affiliation: Department of Advanced Functional Thin Films, Korea Institute of Materials Science (KIMS) , Changwon 51508, Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Advanced Functional Thin Films, Korea Institute of Materials Science (KIMS) , Changwon 51508, Korea.
authors.forename: Byungjin
authors.initials: B
authors.lastname: Cho
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 03760, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Kim
keywords: MoS2; charge transfer; chemical vapor deposition; gas adsorption; work function