High-Performance Solar-Blind Deep Ultraviolet Photodetector Based on Individual Single-Crystalline Zn2GeO4 Nanowire.

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 × 10³ A W⁻¹, external quantum efficiency of 2.45 × 10⁶%, detectivity of ≈2.91 × 10¹¹ Jones, τ_rise ≈ 10 ms, and τ_decay ≈ 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. [ABSTRACT FROM AUTHOR]