Plasma-prepared GaSe films for visible light emitting devices

For the first time, gallium selenide (GaSe) thin films on sapphire (001) were prepared by Plasma-enhanced chemical vapor deposition (PECVD) using high-purity elements Ga and Se as the precursors. The interaction of the elements was initiated by an RF discharge $(40.68 \mathrm{MHz})$ at a reduced pressure of 0.1 Torr. A consistent increase in the plasma discharge power, when other process parameters remaining unchanged, leads to an increase in the structural quality of the films, a decrease in their surface roughness, and an increase in the optical band gap from 1.65 to 2.10 eV. The studied photoluminescent properties of thin GaSe films confirm the improvement in the quality of gallium selenide films with a more intense plasma discharge.