Dual-ultraviolet wavelength photodetector based on facile method fabrication of ZnO/ZnMgO core/shell nanorod arrays

Highlights: • Hydrothermal and RF sputtering were used to construct core/shell structure. • Achieving dual-ultraviolet wavelength photodetection at 254 nm and 365 nm. • The response speed is improved compared with bare ZnO nanorod arrays. -- Abstract: ZnO/ZnMgO core/shell nanorod arrays with a large surface-to-volume ratio and negligible lattice mismatch are considered as a promising candidate applied in ultraviolet photodetection. Herein, ZnO/ZnMgO core/shell nanorod arrays were fabricated by using simple and facile hydrothermal and radio frequency magnetron sputtering methods and applied in the dual-ultraviolet wavelength photodetector successfully. The morphology and crystallization show the formation of core/shell nanorod arrays and typical hexagonal wurtzite structure. The fabricated device demonstrates significant ohmic contact and has a high photo-to-dark current ratio and a fast rise/decay time under the 254 nm and 365 nm illumination at 5 V bias. ZnO/ZnMgO core/shell nanostructure could bring about the speedy separation of photogenerated electron-hole pairs and suppress the recombination of photogenerated carriers because of the formation of built-in electric field in the interfacial region of core/shell structure and the passivated surface states of bare ZnO nanorods. Therefore, our work offers a method to fabricate high performance dual-ultraviolet wavelength photodetector for the potential application in future ultraviolet detection.