Controllable vapor growth of CsPbBr3/CdS 1D heterostructures with type-II band alignment for high-performance self-powered photodetector

Abstract

The controllable growth of semiconductor heterostructures with suitable band alignment and morphology is crucial for the construction of high-performance optoelectronic devices, which is limited to the traditional semiconductor families. Here, high-quality CsPbBr₃/CdS heterostructures with a unique 1D morphology and type-II band alignment have been obtained through a 2-step physical vapor deposition strategy, in which CsPbBr₃ microcubes were grown on the side wall of pre-grown free-standing CdS microwires. Owing to the effective separation and transportation of photogenerated carriers at the CsPbBr₃/CdS heterojunction with type-II band alignment, a photodetector based on a single CsPbBr₃/CdS 1D heterostructure showed high self-powered performances (without additional bias supplies), including I_on/I_off ratio of 3 × 10³, photoresponsivity of 24.5 mA W⁻¹, detectivity of 1.09 × 10¹² Jones, detectable spectral range from 350 nm to 530 nm and response speeds of 1.5 ms (rise time) and 14.9 ms (decay time) at a bias of 0 V. This work provides an effective way for the controllable growth of high-quality CsPbX₃-based 1D heterostructures, which promotes their practical applications in optoelectronic devices without power consumption.