One-dimensional core/shell radial heterojunction with cascade type-II energyband alignment for enhanced broadband photodetection

Constructing a one-dimensional(1D)core/shell heterostructure is a rational and efficient way to integrate multiple functional materials into a single device,in which a distinct and reliable interface and suitable energy-band alignment play important roles in optoelectronic applications.Here,using a typical magnetron sputtering system,we constructed a 1D ZnO/CdS/CdTe core/shell nanorod arrays radial heterojunction with a well-designed cascade type-II energy band alignment and improved the broadband photodetector(PD)performance.The well-formed shell layers compensated for the defect states on the ZnO surface and extended the photoresponse range from ultraviolet to visible and near-infrared.Moreover,reliable and distinct heterointerfaces with a cascade type-II energy band alignment can guarantee more stable carrier migration and reduce energy loss,promoting effective photogenerated charge carrier separation and resulting in an enhanced photoresponse.The optimised 1D ZnO/CdS/CdTe core/shell heterojunction PD exhibited a fast photoresponse at 0 V bias with high responsivity and detectivity.These results provide an important reference for the rational design and controllable synthesis of multifunctional optoelectronic nanodevices.