Multiheterojunction\nPhotodetectors Based on Type-II\nCdSe-CdTe-ZnTe Heterojunctions: Structural Design and Optimization\nfor an Enhanced Transient Response under UV–Vis–NIR\nLight

Ingenious microstructure design and a suitable multicomponent\nstrategy\nare still challenging for improving the photodetector performance.\nIn this paper, vertically arranged CdSe-CdTe-ZnTe core–shell\nnanowire arrays with one-dimensional (1D) bivalve structures have\nbeen successfully synthesized by the vapor–liquid–solid\ngrowth method assisted by gold catalysts. The core–double-shell\nnanowires have an average length of 5 μm and a diameter of 10\nnm and have been applied in the production of ultraviolet–visible\n(UV–vis)–NIR photodetectors. Owing to the cascade band\nedges and the enhanced charge separation, the rate of charge recombination\nis greatly reduced. In addition, the spatially indirect interband\ntransition of photogenerated carriers breaks the limit of photon energy\nabsorption of the single-component material, thus further extending\nthe detection range to near-infrared light and effectively accelerating\nthe transient response of the photodetector from 3.8 to 0.1 s compared\nto that based on the CdSe-CdTe single-shell structure. This work proves\nthat the one-dimensional core–double-shell structure can effectively\nimprove the transient response of the photodetector while still maintaining\nthe piezo-phototronic effect-enhanced performance of the core–shell\nnanowire array.