Surface Energy-Mediated Self-Catalyzed CsPbBr₃ Nanowires for Phototransistors

Controllable self-catalyzed growth of semiconductor nanowires (NWs) is of great importance, particularly to avoid impurities coming from foreign catalysts to deteriorate the NW properties. Although this catalyst-free NW growth has many obvious advantages, there are very limited works focused on all-inorganic CsPbBr₃ perovskite NWs, which is one of the recent champion materials for electronics and optoelectronics. Here, a direct self-catalyzed synthesis of freestanding CsPbBr₃ NWs via vapor–liquid–solid growth mechanism by chemical vapor deposition is developed. Notably, mainipulation of the substrate surface roughness is the key enabling parameter for the self-catalyzed NW growth here. It is revealed that the surface energy of substrates, modulated by its surface roughness, is found to effectively mediate the self-catalytic growth of CsPbBr₃ NWs. When configured into photodetectors, the intrinsic p-type CsPbBr₃ NWs exhibit good optoelectronic performance with a photoresponivity of ≈2000 A W⁻¹, a detectivity of ≈2.57 × 10¹² Jones, and a fast response down to 362 µs. All these results evidently indicate the technological potential of this self-catalyzed synthesizing route for other high-quality all-inorganic perovskite NWs.