Atomically Thin Gallium Nitride for High-Performance Photodetection

Gallium nitride (GaN) technology has matured and commercialised for optoelectronic devices in the ultraviolet (UV) spectrum over the last few decades. Simultaneously, atomically thin materials with unique features have emerged as contenders for device miniaturization. However, the lack of successful techniques to produce ultra-thin GaN prevents access to these new predicted properties. Here, this important gap is addressed by printing millimeter-large ultra-thin GaN nanosheets (NS) (approximate to 1.4 nm) using a simple two-step process that simultaneously introduces nitrogen point defects. This extends the photoelectrical spectral response from UV (280 nm) to near infrared (NIR) (1080 nm). The GaN-based photodetectors display excellent figures of merit, having a responsivity (2.72 x 10(4) A W-1) up to four orders of magnitude higher than the commercial photodetectors at room temperature, despite being 10(2)-10(3) times thinner. The photodetectors exhibit fast switching, with rise and decay time in the range of microseconds. The state-of-the-art device performance originates from the ultra-thin nature of GaN NS coupled with nitrogen point vacancies in the synthesis process. This work presents the opportunity to significantly expand the reach of GaN semiconductor technology and may lead to applications in high-performance miniaturized imaging systems, spectroscopy, communication, and integrated optoelectronic circuits.