本論文主要是研究氧化鎳電子阻障層對於氧化亞銅/氧化鋅異質接面光檢測器在偏壓與自供電(self-powered)時之特性影響。首先將氧化鎳溶液旋轉塗佈於ITO透明導電玻璃基板，再放進烤箱擴散與退火，接著將退火完的元件浸入硫酸銅水溶液且用電化學沉積法沉積氧化亞銅，緊接著將元件濺鍍氧化鋅晶種層於氧化亞銅上，再使用化學水浴沉積法合成氧化鋅奈米柱陣列，最後在氧化鋅奈米柱陣列上濺鍍鉑電極，完成氧化鎳/氧化亞銅/氧化鋅異質光檢測器。
接著量測與分析有無氧化鎳會對於氧化亞銅/氧化鋅異質接面光檢測器特性之影響。擁有氧化鎳之光檢測器在照射450 nm波長之可見光且自供電條件下光暗電流比值為115.08，此結果歸因於氧化鎳為寬能隙P型半導體，對於氧化亞銅之傳導帶有很高的位能障，控制光產生電子的擴散方向，因此照射450 nm波長之可見光時能有效傳輸光產生電子，避免電子往ITO電極擴散而導致電子電洞對的覆合與減少漏電流，由此可知，氧化鎳為有效的電子阻障層。
當照射370 nm波長之紫外光下，量測氧化鎳/氧化亞銅/氧化鋅異質接面所構成之光檢測器， PD在逆向偏壓-1V和自供電模式（0V）下的上升時間分別為66.7s和62ms。 下降時間分別為119秒和24ms，-1V偏壓下的響應時間遠長於零偏壓，由於在自供電時並無逆向偏壓下所提供的外部電子注入，使得產生率約等於覆合率。當逆向偏壓時，由於有大量的電子從ITO側注入，並穿隧氧化鎳，且因為氧化鋅奈米柱材料特性，在照光後使光產生電洞與電子覆合，使產生率遠大於覆合率，進而增加了上升時間，而未照光時之電子電洞對覆合率也降低，因此延長了下降時間。
在逆向偏壓條件下，具有電子阻障層的PD之光電流低於沒有阻障層的PD，由於NiO電子阻障層降低了外部電子注入的能力，使電子隧穿的可能性降低。
本研究之元件具有低成本、製程簡易、低耗能、響應速度快之優點，因此相當有潛力作為光檢測器。

This thesis investigated the reverse biased and self-powered characteristics of the p-Cu_2 O/n-ZnO nanorod heterojunction photodetectors (PD) with a p-NiO electron-blocking layer. First, the nickel oxide solution was spin-coated on an indium tin oxide (ITO) transparent conductive glass substrate and followed by furnace annealing. The p-Cu_2 O film was then electrodeposited onto the p-NiO film and a ZnO seed layer was deposited on the Cu_2 O film using sputtering technique. Subsequently, the ZnO nanorod arrays were synthesized by chemical bath deposition method. Finally, the top electrode Pt film was sputtered onto the ZnO nanorod arrays with a shadow mask.
Under 450 nm visible light illumination and at zero bias (i.e. self-powered), the photo/dark current ratio of the p-NiO/p-Cu_2 O/n-ZnO and p-Cu_2 O/n-ZnO PDs are 115.08 and 6.92, respectively. The significant improvement of the photo/dark current ratio can be attributed to the wide bandgap p-NiO layer, its higher conduction band edge than the cuprous oxide creates a high potential energy barrier for the photo-generated electrons. Because of the energy barrier, it prevent the electrons diffuse to the ITO electrode i.e. it controls the diffusion direction and reduce leakage current, the nickel oxide layer is acting as an effective electron-blocking layer.
When the PD illuminated with 370nm ultraviolet light, the rise time of the PD under a reverse bias voltage of -1 V and at self-powered mode (0V) are 66.7 s and 62 ms, respectively. The fall times are 119 s and 24 ms, respectively. The fall time under -1 V bias is much longer than that of the zero bias. The much faster fall time at zero bias can be attributed to the fact that there is no external electron injection at zero bias, the carriers’ generation rate is approximately on the order of the recombination rate. In contrast to reverse bias mode, the external electron-injection is significant such that it requires much longer time to recover under a steady recombination rate.
Under reverse biased condition, the photo current of the PD having an electron-blocking layer is lower than that of a PD without the blocking layer, the ability of external electron injection is reduced by the NiO electron blocking layer due to a lower chance of electron tunneling.
The studied PD has great potential with advantages of low-cost, simple process, low energy consumption, and fast response time.

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