| Summary: | 碩士 === 國立交通大學 === 光電工程研究所 === 104 === This thesis is about how to growth large area MoS2 and WS2 thin films by sulfurizing the transition metal directly. After the transition metal was deposited on the substrate, X-ray photoelectron spectrum shows that oxidation process occurred before sulfurization, which means that sulfurization process is a chemical process for sulfur atoms replaced by oxygen atoms. Also, according to Raman and photoluminescence spectrums, with proper sulfur powder amount, we can get high quality thin films. After optimizing the growth parameters, we can grow large-area MoS2 and WS2 thin films with controllable thickness. Moreover, with sulfurization process, we can decide the location of thin 2-D crystal films by selective metal deposition, which indicates that the selective growth of 2-D crystals is possible. Also, the WS2 / MoS2/ WS2 double hetero-structures was achieved, showing the possibility to create new material by stacking different kinds of 2-D crystals. As for electronic device application, we can also figure out that the electron mobility and drain current On/Off Ratio are dependent to the layer numbers of the 2-D crystal films .Choosing the suitable layer numbers is necessary to achieve the best performances of the devices.
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