期刊
APPLIED PHYSICS LETTERS
卷 106, 期 25, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.4923202
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资金
- Basic Science Research Program through National Research Foundation of Korea - Korean government Ministry of Science, ICT and Future Planning [2011-0014209]
- National Research Foundation of Korea (NRF) through the SRC Center for Topological Matter [2011-0030787]
- [IBS-R004-G4]
- Ministry of Science, ICT & Future Planning, Republic of Korea [IBS-R004-D1-2015-A00] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
- National Research Foundation of Korea [2011-0030046, 2011-0014209, 10Z20130011056] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
The electrical properties of two-dimensional atomic sheets exhibit remarkable dependences on layer thickness and surface chemistry. Here, we investigated the variation of the work function properties of MoS2 films prepared with chemical vapor deposition (CVD) on SiO2 substrates with the number of film layers. Wafer-scale CVD MoS2 films with 2, 4, and 12 layers were fabricated on SiO2, and their properties were evaluated by using Raman and photoluminescence spectroscopies. In accordance with our X-ray photoelectron spectroscopy results, our Kelvin probe force microscopy investigation found that the surface potential of the MoS2 films increases by similar to 0.15 eV when the number of layers is increased from 2 to 12. Photoemission spectroscopy (PES) with in-situ annealing under ultra high vacuum conditions was used to directly demonstrate that this work function shift is associated with the screening effects of oxygen or water molecules adsorbed on the film surface. After annealing, it was found with PES that the surface potential decreases by similar to 0.2 eV upon the removal of the adsorbed layers, which confirms that adsorbed species have a role in the variation in the work function. (C) 2015 AIP Publishing LLC.
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