Atomically Thin Gallium Nitride for High-Performance Photodetection

摘要

Gallium nitride (GaN) technology has matured and commercialised foroptoelectronic devices in the ultraviolet (UV) spectrum over the last fewdecades. Simultaneously, atomically thin materials with unique features haveemerged as contenders for device miniaturization. However, the lack ofsuccessful techniques to produce ultra-thin GaN prevents access to thesenew predicted properties. Here, this important gap is addressed by printingmillimeter-large ultra-thin GaN nanosheets (NS) (≈1.4 nm) using a simpletwo-step process that simultaneously introduces nitrogen point defects. Thisextends the photoelectrical spectral response from UV (280 nm) to nearinfrared (NIR) (1080 nm). The GaN-based photodetectors display excellentfigures of merit, having a responsivity (2.72 × 10~4 A W~（?1）) up to four orders ofmagnitude higher than the commercial photodetectors at room temperature,despite being 10~2–10~3 times thinner. The photodetectors exhibit fastswitching, with rise and decay time in the range of microseconds. Thestate-of-the-art device performance originates from the ultra-thin nature ofGaN NS coupled with nitrogen point vacancies in the synthesis process. Thiswork presents the opportunity to significantly expand the reach of GaNsemiconductor technology and may lead to applications in high-performanceminiaturized imaging systems, spectroscopy, communication, and integratedoptoelectronic circuits.