Epitaxial growth of CsPbBr₃-PbS vertical and lateral heterostructures for visible to infrared broadband photodetection

Owing to their excellent optoelectronic properties, halide perovskite is very promising for photodetectors and other optoelectronic devices. Perovskite heterostructures are considered to be the key components for these devices. However, it is challenging to rationally synthesize those heterostructures. Here, we demonstrate that perovskite can be epitaxially grown on PbS by vapor transport, thereby creating an interesting CsPbBr₃-PbS heterostructure. Remarkably, photodetectors based on CsPbBr₃-PbS heterostructures exhibit visible to infrared broadband response with room temperature operation up to 2 μm. The room temperature detectivity higher than 1.0 × 10⁹ Jones was obtained in the 1.8- to 2-μm range. Furthermore, the p-n heterojunction exhibits a clear rectifying characteristic and enables detector to operate at zero-bias. Our study provides fundamentally contributes to establish the epitaxial growth perovskite heterostructures and demonstrate a materials platform for efficient perovskite-based optoelectronic devices.