HighPerformance Solar-Blind Deep Ultraviolet Photodetector Based on Individual Single-Crystalline Zn2GeO4 Nanowire

摘要

Solar-blind deep ultraviolet (DUV) photodetectors have been a hot topic in recent years because of their wide commercial and military applications. A wide bandgap (4.68 eV) of ternary oxide Zn2GeO4 makes it an ideal material for the solar-blind DUV detection. Unfortunately, the sensing performance of previously reported photodetectors based on Zn2GeO4 nanowires has been unsatisfactory for practical applications, because they suffer from long response and decay times, low responsivity, and quantum efficiency. Here, high-performance solar-blind DUV photodetectors are developed based on individual single-crystalline Zn2GeO4 nanowires. The transport mechanism is discussed in the frame of the small polaron theory. In situ electrical characterization of individual Zn2GeO4 nanowires reveals a high gain under high energy electron beam. The devices demonstrate outstanding solar-blind light sensing performances: a responsivity of 5.11 x 10(3) A W-1, external quantum efficiency of 2.45 x 10(6)%, detectivity of approximate to 2.91 x 10(11) Jones, (rise) approximate to 10 ms, and (decay) approximate to 13 ms, which are superior to all reported Zn2GeO4 and other ternary oxide nanowire photodetectors. These results render the Zn2GeO4 nanowires particularly valuable for optoelectronic devices.