Plasma-enhanced chemical vapor deposition of Ga x S 1− x thin films: structural and optical properties

Gallium sulfides are wide-gap materials (band gap in the range of 2.85–3.05 eV) that have great potential for applications in optoelectronics, photovoltaics, nonlinear optics, and energy storage. In this study, thin films of gallium sulfide Ga x S 1−x were prepared for the first time by plasma-enhanced chemical vapor deposition using a transport reaction involving chlorine. High-purity elemental gallium and sulfur were directly used as starting materials. The non-equilibrium low-temperature plasma of the RF discharge (40.68 MHz) initiated chemical transformations. The effect of plasma power on the composition, structure, surface morphology, and optical properties of the films was studied. Ga x S 1−x films have sufficiently high transparency in the visible and near-IR ranges (up to 70%).