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Inverted Si:PbS Colloidal Quantum Dot Heterojunction-Based Infrared Photodetector

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journal contribution
posted on 2020-03-23, 04:29 authored by Kaimin Xu, Xiongbin Xiao, Wenjia Zhou, Xianyuan Jiang, Qi Wei, Hao Chen, Zhuo Deng, Jian Huang, Baile Chen, Zhijun Ning
Silicon and PbS colloidal quantum dot heterojunction photodetectors combine the advantages of the Si device and PbS CQDs, presenting a promising strategy for infrared light detecting. However, the construction of a high-quality CQDs:Si heterojunction remains a challenge. In this work, we introduce an inverted structure photodetector based on n-type Si and p-type PbS CQDs. Compared with the existing normal structure photodetector with p-type Si and n-type PbS CQDs, it has a lower energy band offset that provides more efficient charge extraction for the device. With the help of Si wafer surface passivation and the Si doping density optimization, the device delivers a high detectivity of 1.47 × 1011 Jones at 1540 nm without working bias, achieving the best performance in Si/PbS photodetectors in this region now. This work provides a new strategy to fabricate low-cost high-performance PbS CQDs photodetectors compatible with silicon arrays.