High‐Performance Low‐Voltage‐Driven Phototransistors through CsPbBr₃–2D Crystal van der Waals Heterojunctions

Abstract Combining halide perovskites and 2D materials to form heterojunctions is a potential excellent strategy to design high‐performance phototransistors. However, a standard perovskite/2D material heterojunction is not fully realized, because either of the active material usually directly bridges across the opposite metal electrodes in the transistor platform. Here, phototransistors are fabricated based on high‐quality van der Waals grown CsPbBr₃ and MoS₂, in which CsPbBr₃ and MoS₂ are overlapped only within the transistor channel. The phototransistors based on this standard CsPbBr₃/MoS₂ heterojunction exhibit excellent optical detection ability and field‐effect characteristics at a drain–source voltage as small as 0.5 V. The rise and fall times of the phototransistor are 2.5 and 1.8 ms, respectively. The hole mobility is calculated to be 0.08 cm² V⁻¹ s⁻¹ in darkness, and 0.28 cm² V⁻¹ s⁻¹ under the 442 nm laser illumination. All of the measurements are conducted at room temperature in ambient air, indicating the excellent robustness of the CsPbBr₃/MoS₂ heterojunction. This work provides a new strategy to minimize the device size by using low‐voltage‐driven, air‐stable perovskite/2D material heterojunctions.