A visible light detector based on a heterojunction phototransistor with a highly stable inorganic CsPbI_xBr_(3-x) perovskite and In-Ga-Zn-O semiconductor double-layer

摘要

An all-inorganic heterojunction phototransistor using a highly stable perovskite (CsPbl_xBr_(3-x)) and amorphous In-Ga-Zn-O (IGZO) double-layer is introduced to enhance the sensing performance of optoelectronic devices and to expand their detecting range from the ultraviolet to the visible light region. Despite the high-performance photoelectric properties of CsPbl3 perovskites retaining the α-phase, actual applications of the perovskite film are considerably hindered by the phase instability under ambient conditions. Here, in order to improve the long-term stability of the α-phase perovskite, we propose a multiple anion strategy in the perovskite structure. The developed CsPbl_xBr_(3-x) film is applied with bi-anion l_xBr_(3-x) instead of l3 by adding CsBr and PbBr2 in the CsPbl3 precursor solution. Using the optimized CsPbI_xBr_(3-x) film with 12 wt% of the additives CsBr and PbBr2 in the CsPbi3 precursor solution, we demonstrate an all-inorganic visible light detector based on a heterojunction phototransistor with a p~(++)-Si/SiO2/IGZO/CsPbl_xBr_(3-x)/Ti-Al-Ti structure, in which IGZO and CsPbl_xBr_(3-x) are used as a charge transport layer and a light absorption layer, respectively. The phototransistor exhibits a responsivity of 26.48 A W~(-1), a detectivity of 8.42 × 10~(14) Jones, and an external quantum efficiency of 51% under visible light illumination (635 nm). In particular, it shows excellent stability over 1 month under ambient conditions.