High-Responsivity Vis–NIR Photodetector Based on a Ag<sub>2</sub>S/CsPbBr<sub>3</sub> Heterojunction
Fuguo Wang, Haiting Zhang, Xiaoxian Song, Hongwen Li, Ze Xu, Dongdong Wei, Jingjing Zhang, Zijie Dai, Yunpeng Ren, Yunxia Ye, Xudong Ren, Jianquan Yao
Abstract
Quantum dots (QDs) have gained significant interest in optoelectronic devices due to their excellent properties. Single-QD materials limit the high performance of photodetectors (PDs). The performance of PDs is enhanced by combining two dissimilar materials to form a heterostructure. The high responsivity vis–NIR photodetector based on a Ag2S/CsPbBr3 heterojunction is presented in this work. Using CsPbBr3 QDs as the first absorption layer and Ag2S QDs as the second absorption layer, a bipolar carrier transporting channel was built. This layered arrangement can absorb light most effectively. The formation of a heterojunction promoted charge transfer and reduced the recombination of carriers, thus improving the performance of devices. The responsivity (R) is 11.3 A/W, and the specific detectivity (D*) is 3.55 × 1010 Jones for the Ag2S/CsPbBr3 PD under 405 nm irradiation. Meanwhile, the Ag2S/CsPbBr3 heterojunction can absorb 350–1040 nm light, indicating that the device has a wide spectral detection capability (vis–NIR). The response time of the PD is 31/34 ms under 532 nm irradiation. This work provides a feasible way for high responsivity and zero-dimensional heterojunction photodetectors.