本論文利用氧氣吸附於石墨烯表面造成其內部之載子濃度改變來獲得p型半導體特性的石墨烯。實驗中，利用熱化學氣相沉積法製作石墨烯，並利用氮電漿對石墨稀進行摻雜，以C-N的鍵結讓石墨烯的半導體特性由p型轉變為n型。氮電漿處理是一個能有效調變石墨烯半導體特性的方法。在石墨烯電晶體的電壓-電流特性曲線量測中以迪拉克點(電壓-電流曲線中的最低點)為分界可觀察到電子與電洞的工作區。經過不同的氮電漿處理時間可以調整石墨烯中的載子比例進而控制其半導體特性。未摻雜之p型石墨烯其電壓-電流特性曲線由電洞主導;而隨著氮含量上升，其電壓-電流曲線中的最低點逐漸位移至-38 V，而電子濃度則大於電洞濃度。本論文除了成功地對於石墨烯進行半導體特性改質，也將p型石墨烯與n型的二硫化鉬結合，製作異質接面二極體。二硫化鉬的能帶結構會隨著材料的厚度降低造成能隙上升。透過控制二硫化鉬厚度進行材料能隙調變，因此與石墨烯結合製作而成的二極體元件會具有不同的開啟電壓。由二極體特性曲線量測可發現到元件因為二硫化鉬能隙的調變具有不同的內建障壁電位。研究中亦針對二硫化鉬的半導體特性與能帶結構的分析進行深入討論。利用Mo1-xWxS2化學式對二硫化鉬中進行鎢原子摻雜，利用此材料特殊的能帶結構並製作光偵測元件，探討能帶彎曲特性與光響應度之間的關係。最後結合p型半導體特性的石墨烯與Mo1-xWxS2在不同的鉬鎢比例下(x = 0-1, Δx = 0.1)造成的能帶彎曲效應製作異質接面二極體。在特性曲線量測上發現元件在不同的鎢含量下呈現不同的內建障壁電位。Mo1-xWxS2的電子親和力隨著鎢含量增加而降低，由此結果我們可以得到一個新的元件設計架構與應用。

In this thesis, we could precisely confirm the semiconducting type of graphene by the changing of interior carrier concentration and resistivity when O2 gas adsorbed onto graphene surface. Multilayer graphene was directly grown onto Cu foils using thermal chemical vapor deposition (TCVD). The nitrogen plasma treatment was used to introduce nitrogen atoms into the graphene. The plasma treatment duration was the parameter used to control the multilayer graphene nitrogen content. In the semiconductor materials analysis we confirm whether the multilayer graphene is p- or n-type by measuring the Dirac point (minimum in I-V characteristic) of graphene-based field effect transistors (GFETs). Generally, the nitrogen content increased with the increase in nitrogen plasma treatment time. On the contrary, the current of the n-type graphene will decrease while the electrons, the main carriers, are captured by the O2 molecules on the surface resulting in the reduction of the electron concentration. Moreover, we measured the Dirac point of GFETs to confirm whether the graphene is p- or n-type. As the nitrogen content of graphene increased, the Dirac point shifts negatively to -38 V, which means that the electron concentration is larger than the hole concentration. Besides, the MoS2 layers were formed by the mechanical exfoliation method. The MoS2 band-gap increases with decreasing thickness. The I-V characteristics of the MoS2/Graphene heterojunction diodes can be precisely tuned by adjusting different thicknesses of the MoS2 films. By applying our fabricating method, MoS2/Graphene heterojunction diode can be easily constructed and have potential to different applications. On the other hand, we investigated the photoconductive characteristics of tungsten-substituted molybdenum disulfide (Mo1-xWxS2) series materials synthesized by the chemical vapor transport (CVT) method using different x values of W compositions (x = 0-1, Δx = 0.1). We applied the Mo1-xWxS2 series materials to photoconductive detectors and then measured the photoresponse properties. In the two-dimensional component design and application, the Mo1-xWxS2 electron affinity decreases with increasing x value of tungsten (W) composition (x = 0.0-1.0, Δx = 0.2). The I-V characteristics of the Mo1-xWxS2/graphene heterojunction diodes can be accurately tuned by conduction band bowing effect with different W composition of the Mo1-xWxS2 films. By applying our fabricating method, the Mo1-xWxS2 with different W composition provides a new application of semiconductor device.

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