Cu₂ZnSnS₄ (CZTS) has been extended to the field of photodetection owing to its outstanding optoelectronic properties. However, the existence of the ineluctable defects in CZTS semiconductors affects and even determines the optoelectric processes including carrier generation, relaxation, transfer, and recombination. Moreover, photoresponse correlated to the defects in CZTS photodetectors has not well been documented and the possible physics mechanism is still unexplored. High-performance and self-powered PN heterojunction photodetectors are built from Cu₂ZnSnS₄ and CdS films. The devices exhibit a steady rectifying behavior and a prominent photovoltaic effect. The peak values of responsivity and detectivity are 220 mA W^–1 and 2.69 × 10¹⁰ Jones, respectively. A very fast response speed with rising and decay times of up to 18 and 19 μs and an ultrahigh photoswitching ratio beyond 10⁴ are demonstrated in these photodetectors. An abnormal dependence of the light response parameters on the incident power and temperature is found in these devices. This anomaly is explained by the formation of the defects and/or defect dipoles, which are evidenced by the temperature dependence of the photocurrent, the dependence of the capacitance on the bias voltage at different temperatures, and the derivative of capacitance with temperature.

中文翻译：

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在自供电 Cu2ZnSnS4/CdS PN 异质结中具有超高光开关比和极快响应速度的高性能光电探测器

Cu ₂ ZnSnS ₄ (CZTS)由于其出色的光电特性已扩展到光电检测领域。然而，CZTS半导体中不可避免的缺陷的存在影响甚至决定了载流子产生、弛豫、转移和复合等光电过程。此外，与 CZTS 光电探测器缺陷相关的光响应还没有得到很好的记录，可能的物理机制仍未得到探索。高性能和自供电 PN 异质结光电探测器由 Cu ₂ ZnSnS ₄和 CdS 薄膜构成。该器件表现出稳定的整流行为和突出的光伏效应。响应度和检测度的峰值为 220 mA W ^–1和 2.69 × 10 ¹⁰琼斯，分别。这些光电探测器展示了非常快的响应速度和高达 18 和 19 μs 的上升和衰减时间以及超过 10 ⁴的超高光开关比。在这些器件中发现光响应参数对入射功率和温度的异常依赖性。这种异常可以通过缺陷和/或缺陷偶极子的形成来解释，这可以通过光电流的温度依赖性、不同温度下电容对偏置电压的依赖性以及电容随温度的导数来证明。