Two-dimensional GaN: Preparation Based on Liquid Metal Gallium and Photoelectric Properties

Two-dimensional (2D) gallium nitride (GaN) exhibits broad application prospects in the field of ultraviolet optoelectronics due to its dual characteristics of wide-bandgap semiconductor and quantum confinement effect. However, conventional synthesis methods for 2D GaN, such as metal-organic chemical vapor deposition and molecular beam epitaxy, typically require high growth temperatures, prolonged processing time, and relatively high costs. To address these critical challenges, this work leverages the intrinsic properties of liquid metal gallium, including its low melting point and ease of oxidation to develop an efficient and relatively low-temperature synthesis strategy for 2D GaN. The core of this strategy includes following steps. Firstly, utilizing a straightforward spin-coating exfoliation technique to directly extract an amorphous gallium oxide (Ga2O3) from the surface of liquid gallium. Subsequently, subjecting the amorphous Ga2O3 to a nitridation treatment process at a relatively low temperature of 850 ℃, successfully achieved its conversion into high-crystalline-quality GaN. Characterization results demonstrate that the synthesized 2D GaN possesses a thickness of approximately 2.2 nm, a lateral dimension on the centimeter scale, and a hexagonal wurtzite crystal structure. Furthermore, based on the prepared 2D GaN, a photoconductive ultraviolet photodetector is constructed. Performance characterization results reveal that under a 5 V bias voltage and illumination by 325 nm ultraviolet light, the device exhibits a responsivity of 4.14 A/W and a high detectivity of 1.02×1013 Jones. This study demonstrates the successful preparation of large-area 2D GaN material based on liquid gallium metal, providing a valuable reference for the development of low-dimensional and high-performance ultraviolet photodetectors.