甲胺铅卤钙钛矿因具备高光吸收系数、宽带隙调节能力，成本低、易制备等优势，被广泛应用于光电探测器领域。目前钙钛矿研究材料的制备的时间和经费消耗成本高，而器件结构设计依托于前人经验难以针对化或创新。以此为出发点，研究旨在通过可信的TCAD仿真计算来揭示器件设计关键问题对光电探测器性能的影响，并辅以实验验证，主要内容如下：根据现有的传统半导体仿真机理，结合甲胺铅卤钙钛矿材料的有机-无机特性及缺陷容忍特性，组合了仿真机理。考虑了包括迁移率随掺杂浓度和电场的变化，复合随缺陷态密度和高载流子密度的变化，缺陷辅助隧穿效应，有机材料界面态等因素的影响，并搭建了FTO/TiO2/MAPbI3/Spiro-OMeTAD/Au结构光电探测器。对上述器件进行仿真，系统地探讨了钙钛矿吸收层MAPbI3的厚度、缺陷态密度对光电探测器性能的影响。结果揭示了厚度对器件性能的影响需要与器件的工作波长、缺陷态密度综合考虑。验证了钙钛矿的浅缺陷容忍特性，以及深能级缺陷显著裂化器件性能的传统理论。根据高密度浅缺陷仿真出现的性能明显下降，提出了浅缺陷态密度阈值影响，推断其原因为过高的浅缺陷密度影响到了载流子输运的动态平衡，展现出等同于辐射复合的复合效果。通过与实验文献结果的对应，说明了仿真工作的精准可信性。针对甲胺铅卤独特的更改前驱体配比能够更改掺杂浓度和卤素组合的制备方法，还仿真了材料的掺杂浓度和卤素混合对器件性能的影响。结果显示了掺杂浓度升高降低性能，原因是空间电荷区宽度的减小。在保证能带匹配、探测光波段高效吸收的前提下卤素混能实现器件性能的提升。为制备混合卤素器件，研究首先通过晶格失配性计算，选取以甲胺铅溴为基底的实验路线。首先通过两步法制备了高性能的厘米级甲胺铅溴单晶，然后通过热离子交换制备了混合卤素的异质结器件。通过材料表征展现了混合卤素器件对应的禁带宽度的调节以及吸收光谱的优化，通过电学测试观察到异质结的暗电流降低、光电流高、响应速度快等特性，进一步验证了仿真结果。
Lead halide perovskites with methylammonium (MAPbI3) have been widely applied in the field of photodetectors due to their high light absorption coefficient, wide bandgap tunability, low cost, and ease of preparation. Currently, the preparation of perovskite research materials requires significant time and financial resources, and device structure design relies heavily on previous experience, making it difficult to customize or innovate. Starting from this point, the research aims to reveal the impact of key issues in device design on the performance of photodetectors through reliable TCAD simulation calculations and to corroborate these findings with experimental verification. The main content is as follows:Based on the conventional semiconductor simulation mechanism, the simulation combines the organic-inorganic characteristics and defect tolerance features of methylammonium lead halide perovskite materials. It considers the effects of various factors, including the change in mobility with doping concentration and electric field, recombination with defect state density and high carrier density, defect-assisted tunneling effect, and the interface states of organic materials, and constructs an FTO/TiO2/ MAPbI3/Spiro-OMeTAD/Au structure photodetector.The simulation systematically explores the impact of the perovskite absorption layer MAPbI3's thickness and defect state density on the performance of photodetectors. The results reveal that the impact of thickness on device performance needs to be considered in conjunction with the device's operational wavelength and defect state density. It confirms the shallow defect tolerance nature of perovskites and the traditional theory that deep-level defects significantly deteriorate device performance. Based on the significant performance decline observed in simulations with high shallow defect densities, it proposes an influence threshold for shallow defect state density, suggesting that an excessively high shallow defect density disrupts the dynamic equilibrium of carrier transport, resulting in a recombination effect akin to radiative recombination. By correlating with experimental literature results, the simulation work's accuracy and reliability are demonstrated.Considering the unique property of changing precursor ratios to alter doping concentration and halogen composition in methylammonium lead halides, the simulation also examined the effect of material doping concentration and halogen mixing on device performance. Results show that increased doping concentration reduces performance due to the narrowing of the space charge region width. Under the premise of ensuring band alignment and efficient absorption in the detection wavelength range, halogen mixing can enhance device performance.For the preparation of mixed-halide devices, the study first selected an experimental route based on methylammonium lead bromide as the base through lattice mismatch calculations. It prepared high-performance centimeter-scale methylammonium lead bromide single crystals using a two-step method and then produced mixed-halide heterojunction devices through thermal ion exchange. Material characterization demonstrated the adjustment of the bandgap width and optimization of the absorption spectrum for mixed-halide devices. Electrical testing observed characteristics such as reduced dark current, high photocurrent, and fast response in the heterojunction, further validating the simulation results.
