Er掺杂Cs₂AgBiBr₆薄膜光电探测性能研究

Performance Study of Er-Doped Cs₂AgBiBr₆ Thin Film Photodetectors

摘要: 无铅双钙钛矿结构的Cs₂AgBiBr₆材料是间接带隙半导体，具有光电转化效率高、吸光性能优、带隙可调节且环境友好的特性，在光电器件中有较好的应用前景。本工作采用热蒸发镀膜法在Si/SiO₂基底上成功制备了镧系元素Er掺杂的Cs₂AgBiBr₆薄膜，并将其应用于平面光导型光电探测器件(PPDs)。通过SEM、XRD、EDS等方法分析退火条件对薄膜的相组成及微观形貌的影响，采用光吸收及荧光测试分析薄膜的光学性能，并测试分析所制备光电探测器件的光电流、响应率、探测率等性能。研究表明，Er³⁺掺杂Cs₂AgBiBr₆后样品的光电探测性能得到提升，其中Er原子比为0.25时性能最优。在波长为365 nm和530 nm的光照下，探测率和响应度均比未掺杂的样品提升了4倍。适量稀土元素的掺杂可降低钙钛矿材料内部结构的缺陷，提高光电响应。

Abstract: Lead-free double perovskite Cs₂AgBiBr₆ material is a kind of indirect band gap semiconductor, which has the characteristics of high photoelectric conversion efficiency, excellent light absorption performance, adjustable band gap and environmental friendliness, and has a good application prospect in photoelectric devices. In this work, Cs₂AgBiBr₆ thin films doped with lanthanide Er were successfully prepared on Si/SiO₂ substrates by thermal evaporation method, and applied to planar photoconductive photodetectors (PPDs). The effects of annealing conditions on the phase composition and micro-morphology of the films were analyzed by SEM, XRD and EDS. The optical properties of the films were analyzed by light absorption and fluorescence testing, and the photocurrent, responsivity and detectivity of the prepared photodetectors were tested and analyzed. The results show that the photoelectric detection performance is improved after Er³⁺ doping Cs₂AgBiBr₆, and the performance is the best when the Er atom ratio is 0.25. Under the illumination with wavelength of 365 nm and 530 nm, the detectivity and responsivity are four times higher than those of un-doped samples. The experimental results show that the doping of rare earth elements can reduce the defects in the internal structure of perovskite materials and improve the photoelectric response.