Chemical Vapor Deposition Growth of Two-Dimensional Monolayer Gallium Sulfide Crystals Using Hydrogen Reduction of Ga₂S₃

Abstract

Two-dimensional gallium sulfide (GaS) crystals are synthesized by a simple and efficient ambient pressure chemical vapor deposition (CVD) method using a single-source precursor of Ga₂S₃. The synthesized GaS structures involve triangular monolayer domains and multilayer flakes with thickness of 1 and 15 nm, respectively. Regions of continuous films of GaS are also achieved with about 0.7 cm² uniform coverage. This is achieved by using hydrogen carrier gas and the horizontally placed SiO₂/Si substrates. Electron microscopy and spectroscopic measurements are used to characteristic the CVD-grown materials. This provides important insights into novel approaches for enlarging the domain size of GaS crystals and understanding of the growth mechanism using this precursor system.