Centimeter-scale synthesis of monolayer WS2 for high performance photodetectors by face to face chemical vapor deposition
碩士 === 國立臺灣大學 === 應用物理研究所 === 107 === In this thesis, I will discuss the large area synthesis of monolayer tungsten disulfide (WS2), its optical characterization and application to highly sensitive photodetectors. We first try to find a large-area and highly-efficient method for synthesizing WS2. Th...
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| Format: | Others |
| Language: | en_US |
| Published: |
2019
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| Online Access: | http://ndltd.ncl.edu.tw/handle/5gxq4n |
| Summary: | 碩士 === 國立臺灣大學 === 應用物理研究所 === 107 === In this thesis, I will discuss the large area synthesis of monolayer tungsten disulfide (WS2), its optical characterization and application to highly sensitive photodetectors.
We first try to find a large-area and highly-efficient method for synthesizing WS2. The different chemical vapor deposition methods are discussed and a novel method is proposed where a pre-deposited tungsten film acts as a source of uniform precursor resulting in WS2 films that cover 70 square centimeters in one CVD step.
We then investigate the optical characteristics of the thus produced material and observe a photoluminescence enhancement of WS2 generated by sodium catalyst (WS2-Na). The compound is slightly doped, thus causing a change in the recombination mechanism of the WS2 and improving the carrier recombination efficiency. The WS2-Na photoluminescence intensity is four times higher than that of mechanically exfoliated WS2.
Finally, we use our synthesized WS2 to make photodetector. Since the size of the single crystal is larger than one hundred micrometers, we can easily make single-crystal devices. The WS2 photodetector we produced has a high performance with a responsivity that reaches 4×〖10〗^5A/W and response times that are shorter than 200 microseconds.
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