Piezophototronic Effect Enhanced UV/Visible Photodetector Based on ZnO/ZnSe Heterostructure Core/Shell Nanowire Array and Its Self-Powered Performance

To advance the photodetection capabilities of type II core/shell nanowire-based photodetectors, ZnSe has been employed to coat on ZnO nanowire array creating a type-II heterojunction core/shell nanowire array with additional lower indirect band gap (approximate to 1.84 eV), via a facile two-step process of chemical vapor deposition and pulse laser ablation. The integrated photodetector based on the ZnO/ZnSe core/shell structure is capable of detecting the entire range of the visible spectrum, from blue to red excitation source, as well as UV light. The absolute sensitivity and the percentage change in responsivity of the photodetector are enhanced by one and three orders of magnitude, respectively. The whole range visible light photodetection and enhanced photocurrent response are attributed to the unique ZnO/ZnSe energy band realignment and the piezophototronic effect. Moreover, the photodetector exhibits self-powered photodetection behavior under UV/visible light illumination. This study grants a potential application using ZnO/ZnSe type II heterostructure core/shell nanowire array for broad band UV/visible photodetection in both powered and self-powered circumstances.