隨著光電元件朝向高靈敏度、寬頻響應與微型化方向發展，新型二維材料因其原子級厚度、可調控能帶結構與優異載子傳輸特性，逐漸成為次世代光偵測器的重要候選材料。其中，石墨烯具有極高載子遷移率與優異導電特性，可作為高速載子傳輸通道；而二硫化鉬（ MoS₂）以及傳統半導體材料 (如Si、GaAs、InP）則具備良好的光吸收能力以及不同的能隙，可作為吸光層。透過異質結構設計，可將載子傳輸與光吸收功能分離，進而提升元件的特性。然而，目前二維材料光偵測器之操作機制仍存在不同解釋，特別是在高響應度來源方面，究竟是由傳統的光激載子的收集形成光電流或是由於吸光層的載子累積所導致的通道層費米能階調變之光閘效應 (Photogating Effect）存需進一步釐清。此外，材料層數、基板種類、摻雜濃度與介電層插入等因素，皆可能對元件操光電特性與響應時間產生重要影響。本研究利用石墨烯作為載子通道層，製備石墨烯/二硫化鉬異質結構光偵測器，並探討其光閘效應主導之元件運作機制。透過分析具不同能隙的半導體材料作為吸光層之石墨烯/半導體異質結構光偵測器，比較不同材料系統之響應度與波長響應範圍。此外，本研究亦於傳輸層及吸光層中加入氧化鋁介電層，運用吸光層表面因照光所產生之電偶極對二維材料通道之費米級的影響，以此電偶極誘發之光響應效應製作出二維材料/氧化鋁/半導體偵測器並觀察到此元件相較於光閘效應偵測器較短的反應時間。透過系統性比較光閘效應與電偶極誘導機制之差異，本研究建立二維材料異質結構光偵測器之整體物理模型，並分析材料層數、基板選擇與介面處理對元件性能之影響。研究結果可為未來高靈敏度、快速響應與寬頻光偵測元件之設計提供重要參考，並促進二維材料於新世代光電元件之應用發展。

This thesis presents a systematic study on two-dimensional (2D) material-based photodetectors, focusing on the optimization of device performance through mechanism engineering, material selection, and structural design. The primary objective is to achieve high responsivities while suppressing dark currents. Various heterostructures are investigated, including graphene, molybdenum disulfide (MoS₂), and non-graphene 2D materials such as germanene and stanene as channel layers, combined with different semiconductor substrates (Si, InP, GaAs, and In₀.₁₅Ga₀.₈₅As) as light absorption layers. Two major operating mechanisms, namely the photo-gating effect and dipole-induced photo-response, are systematically analyzed and compared.

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