Here we report band structure design, fabrication and characterization of a novel ultraviolet photodetector which functions based on the heterostructure between silicon, zinc Oxide, and titanium dioxide nanostructures. For this purpose, Zinc Oxide nanowires were grown on p-type (100) oriented silicon wafer by hydrothermal method and covered by a ∼20nm film of titanium dioxide which were deposited by chemical vapor deposition (CVD) method. Results reveal that in forward bias, the shell titanium dioxide layer reduces the dark current and enhances the sensitivity of photodetector, while in reverse bias titanium dioxide layer increases the responsivity. Responsivity and sensitivity as high as 2.5 A/W and 0.95 are obtained in this work, respectively. In our structure, photocurrent showed a linear dependence to illumination intensity. This linearity together with short response time demonstrate that the titanium dioxide nanostructure lowered the effect of trap states on the photo-response of the device, therefore, the dominant role in photocurrent generation was found to be related to the band structure design of the device.

中文翻译：

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使用二氧化钛纳米粒子增强基于 p-硅/n-氧化锌的光电探测器的响应度和灵敏度

在这里，我们报告了一种新型紫外光电探测器的能带结构设计、制造和表征，该探测器基于硅、氧化锌和二氧化钛纳米结构之间的异质结构发挥作用。为此，通过水热法在 p 型（100）取向的硅晶片上生长氧化锌纳米线，并用化学气相沉积（CVD）法沉积的~20nm 二氧化钛薄膜覆盖。结果表明，在正向偏压下，壳层二氧化钛层降低了暗电流，提高了光电探测器的灵敏度，而在反向偏压下，二氧化钛层增加了响应度。在这项工作中分别获得了高达 2.5 A/W 和 0.95 的响应度和灵敏度。在我们的结构中，光电流显示出对光照强度的线性依赖性。