基于低缺陷ZnO电子传输层的PbS量子点光电探测器研究

Research on PbS quantum dots photodetector based on low defects ZnOelectron transport layer

PbS胶体量子点因其光吸收系数高、制备成本低、沉积工艺简单、带隙可调等优点,成为备受关注的新型红外探测纳米材料。光电二极管结构的PbS量子点光电探测器通常使用高透过率、高电子迁移率的ZnO来制备N型层,以加快光生载流子的分离和提取。但是通过溶胶-凝胶法制备的ZnO薄膜在制备过程中会在薄膜中产生缺陷,限制ZnO层性能的发挥。本文通过调节ZnO前驱体溶液的浓度成功制备出缺陷更低的ZnO薄膜并应用于ZnO/PbS光电探测器件,经测试,当溶液浓度为0.7M(mol/L)时,所制备的器件表现出最佳的性能,在1 600 nm处的响应度和探测率分别为0.32A/W和3.48×1011Jones,外量子效率为25%,器件的响应时间为τR=130μs,τF=20μs。这项工作为PbS量子点光电器件性能的优化提供了新的解决方案。

PbS colloidal quantum dots have emerged as a new type of infrared sensing nanomaterial due to their high optical absorption coefficient, low preparation cost, simple deposition process, and tunable band gap.PbS quantum dot photodetectors with photodiode structures typically use ZnO with high transmittance and high electron mobility to prepare N-type layers in order to speed up the separation and extraction of the photogenerated carriers. However, ZnO thin films prepared using the sol-gel method will have defects during the preparation process, limiting their performance.In this paper, ZnO thin films with lower oxygen content defects were successfully prepared by adjusting the concentration of ZnO precursor solution and applied to ZnO/PbS photodetector. The results show that the prepared device showed the best performance when the solution concentration was 0.7M (mol/L). At 1 600 nm, responsivity and detection rate were found to be 0.32A/W and 3.48 ×10 11 Jones, respectively, the external quantum efficiency is 25%, and the response time of the device is τ R =130μs, τ F =20μs.This work provides a novel solution to optimize the performance of PbS quantum dot optoelectronic devices.