本論文利用化學氣相沉積法成長大面積的n型二硫化鉬，透過拉曼光譜儀、光激發螢光與原子力顯微鏡進行分析，結果顯示此二硫化鉬薄膜為單層直接能隙的半導體. 然而氧電漿處理為最直接且能有效的改變二硫化鉬半導體特性的方法. 因此利用氧電漿對二硫化鉬進行摻雜，利用X光光電子能譜儀分析顯示為Mo6+的峰值出現，讓二硫化鉬的半導體特性由n型轉變成為p型，歸因於在表面形成的MoO3. 經由二硫化鉬電晶體的量測特性曲線中，其最低點隨著氧電漿摻雜瓦數的增加，由負區間 -45 V逐漸位移至正區間 50 V，成功地改變二硫化鉬的半導體特性. 本實驗除了將二硫化鉬進行半導體特性改質，也將p型與n型二硫化鉬做結合，利用不銹鋼基板當遮罩選定摻雜區域，以製作同質接面pn二極體. 透過電流-電壓特性的量測，其內建電位障從2.7 V位移至4.3 V，得知表面形成的MoO3有關，因此能透過不同瓦數的摻雜，控制其內建電位障. 二硫化鉬同質接面pn二極體呈現了良好的整流現象，對於未來二極體的應用有非常高的發展性.

In this thesis, a large area of n-type molybdenum disulfide (MoS2) was fabricated by thermal chemical vapor deposition (CVD). The results of Raman spectrum, photoluminescence (PL) and atomic force microscope (AFM) showed that the synthesized MoS2 was single layer and direct bandgap semiconductor material. To transform the characteristics of MoS2 from n-type to p-type, the oxygen plasma treatment with different radio-frequency (RF) powers was conducted. X-ray photoelectron spectroscope (XPS) analysis showed that the peak of Mo6+ mainly changed the properties of MoS2 from n-type to p-type, resulting from the surface formation of MoO3. In the field effect transistor (FET) measurement, as the MoS2 treated with the RF power increased, the current-voltage (I-V) curve of the lowest point shifted from -45 to 50 V, confirming the MoS2 changed from n-type to p-type successfully. In order to fabricate a homojunction pn diode, we defined a plasma treatment region with a mask on MoS2 surface for doping accurately. The I-V characteristic was measured to analyze the pn diode, and the built-in potential barrier was shifted from 2.7 to 4.3 V. Therefore, the built-in potential barrier could be controlled with different RF powers. Furthermore, the MoS2 homojunction pn diode demonstrated good rectification behaviors, we expect that it can be widely applied in the future.

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