A High Performance Solar-Blind Detector Based on Mixed–Phase Zn0.45Mg0.55O Alloy Nanowires Network

Abstract

The mixed-phase Zn0.45Mg0.55O alloy nanowires network was firstly synthesized on SiO2/Si substrate by chemical vapor deposition method. The metal–semiconductor–metal structured Zn0.45Mg0.55O nanowires solar-blind photodetector with a sharp absorption peak of wavelength 245 nm was fabricated, which exhibited an ultra-low dark current (0.2 nA), a high on–off ratio (2.85 × 103), a large peak responsivity (0.48 A/W) at 6 V bias, and a high external quantum efficiency (234.2%). This excellent performance is comparable with other ZnMgO thin film UV photodetectors. Moreover, the detection mechanism of this photodetector is explained by the modifications in energy band diagrams of different nanojunctions among Zn0.45Mg0.55O nanowires and heterojunction interfaces between wurtzite and cubic structured ZnMgO in mixed-phase Zn0.45Mg0.55O nanowire. It is found that nanojunctions and heterojunction interfaces could be responsible for a low dark current and high responsivity of this device based on mixed-phase Zn0.45Mg0.55O nanowire materials. This work reveals that the distinctive advantages of mixed-phase ZnMgO nanowires network for ultraviolet optoelectronic detection applications.