Influence of Gas Adsorption and Gold Nanoparticles on the Electrical Properties of CVD-Grown MoS2 Thin Films

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• 作者：Yunae Cho ; Ahrum Sohn ; Sujung Kim ; Myung Gwan Hahm ; Dong-Ho Kim ; Byungjin Cho ; Dong-Wook Kim
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 24, 2016
• 年：2016
• 卷：8
• 期：33
• 页码：21612-21617
• 全文大小：324K
• 年卷期：0
• ISSN：1944-8252

文摘

Molybdenum disulfide (MoS<sub>2sub>) 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>2sub> is crucial for its application in electronic and optoelectronic devices. Because the MoS<sub>2sub> 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>2sub>, H<sub>2sub>/N<sub>2sub>, and O<sub>2sub>) choice on the resistance (R) and surface work function (WF) of trilayer MoS<sub>2sub> thin films grown via chemical vapor deposition. We also studied the electrical properties of gold (Au)-nanoparticle (NP)-coated MoS<sub>2sub> 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 MoS<sub>2sub> 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 MoS<sub>2sub>.