隨著自駕車、3D 感測、消費性電子產業的興起，紅外光檢測器市場需 求大幅提升，本論文主要研究為 2D-MoS2/單晶鍺薄膜/矽基結構之蕭特基 接面光檢測器以取代昂貴的 InGaAs 光檢測器，使 LiDAR 等紅外光檢測器 產品的生產成本得以大幅下降。 論文中分為三部分進行說明:(一) PVD 之磁控濺鍍法於矽基板成長單 晶鍺薄膜，透過製程參數的優化，由 XRD 與 TEM 等結果研究證實鍺薄膜 具有高度結晶且為(400)的結晶方向，最佳之樣品其 XRD 半高寬為 0.717°， 作為光檢測器之主動層;(二) 利用少量的前驅物與乘載氣體製作高品質的 單層直接能隙 2D-MoS2 薄膜，透過製程參數的優化，得到薄膜拉曼光譜∆k 為 19.97 cm-1 之 2D-MoS2 單層薄膜。PL 與吸收光譜量測證實 MoS2 為直接 能隙，TEM量測MoS2層間距為0.617 nm與理論非常地符合，並且成功轉 印單層 MoS2 至單晶鍺薄膜基板上，作為光檢測器之蕭特基接面的能障層; (三) 整合以上材料製作2D-MoS2/單晶鍺薄膜/矽基結構之蕭特基接面光檢 測器，量測元件證實指叉狀電極寬度縮小至3 μm時響應度獲得大幅度的提 升，並且於 2.5 V 時響應度最高達 0.22 A/W。;With the rise of autonomous vehicle, 3D sensing, and consumer electronics industries, the market demand for infrared photodetectors has increased significantly. In this research, the Schottky-junction photodetectors with the structure of 2D-molybdenum disulfide/germanium/ silicon substrate have been developed to replace the expensive InGaAs photodetectors to reduce the production cost of infrared photodetectors, LiDAR. This research has been divided into three parts: (1). The single crystal germanium films were grown by using magnetron sputtering method on silicon substrates. Through the process optimization, the single crystalline germanium film has been achieved and confirmed by the results of XRD and TEM shown the crystallographic direction of (400). The best XRD full-width at half-maximum of the germanium film is 0.717°, which can be applied as the active layer of the photodetector. (2). The fabrication of high-quality monolayer MoS2 thin films with direct energy gap by using a small amount of precursors and carrier gas. Through the process optimization, the Raman spectrum Δk of the film was 19.97 cm-1, which confirmed that MoS2 was a monolayer film. PL and absorption spectroscopy measurements confirmed that MoS2 film is a direct bandgap material. The interlayer spacing of monolayer MoS2 measured by TEM is 0.617 nm, which is in good agreement with the theoretical thickness. And the monolayer MoS2 was successfully transferred to the single-crystal germanium substrates to be the energy barrier layer for the Schottky junction of the photodetector. (3). The integration of the above materials to fabricate the Schottky-junction photodetectors with the structure of 2D-molybdenum disulfide/germanium/ silicon substrate. The photodetector measurement results have confirmed that the photo-responsivity was greatly improved when the width of the interdigitated electrode was reduced to 3 μm, and the responsivity was up to 0.22 A/W at 2.5 V.
