1D ZnO nanostructures have been widely explored due to their potential applications in ultraviolet (UV) region photodetectors because of their unique structural and optoelectronic properties. However, a large number of surface defect states leading to a noticeable dark current hinders their practical applications in UV photodetection. In this work, we have shown improved ZnO/Al2O3 core-shell microrod photodetectors, whose performance is significantly enhanced by defect passivation and the introduction of trap states by atomic layer deposition grown thin amorphous Al2O3 shell layer, as evidenced by steady-state and transient photoluminescence investigations. The photodetectors demonstrated suppressed dark current and increased photocurrent after capping the Al2O3 layer. Specifically, the ZnO/Al2O3 core-shell microrod photodetector exhibited a photoresponsivity as high as 0.019 A/(W cm-2) with the dark current as low as ∼1 × 10-11 A, and a high I light/I dark ratio of ∼104 under relatively weak light illumination (∼10 μW cm-2). The results presented in this work provide valuable pathways to boost the performance of 1D ZnO microrod-based photodetectors for future practical applications.

中文翻译：

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通过薄非晶 Al2O3 壳层的表面覆盖提高 ZnO 微棒金属-半导体-金属光电探测器的性能

一维 ZnO 纳米结构因其独特的结构和光电特性而在紫外 (UV) 区域光电探测器中具有潜在的应用价值，因此得到了广泛的探索。然而，大量的表面缺陷状态导致明显的暗电流阻碍了它们在紫外光电检测中的实际应用。在这项工作中，我们展示了改进的 ZnO/Al2O3 核壳微棒光电探测器，其性能通过缺陷钝化和通过原子层沉积生长的薄非晶 Al2O3 壳层引入陷阱态而显着增强，如稳态和瞬态所证明的光致发光研究。在覆盖 Al2O3 层后，光电探测器表现出抑制的暗电流和增加的光电流。具体来说，ZnO/Al2O3 核壳微棒光电探测器表现出高达 0.019 A/(W cm-2) 的光响应性，暗电流低至 ∼1 × 10-11 A，高 I 光/I 暗比为 ∼ 104 在相对较弱的光照下 (∼10 μW cm-2)。这项工作中提出的结果为提高基于 1D ZnO 微棒的光电探测器的性能提供了宝贵的途径，以用于未来的实际应用。