• Eriguchi, Kazutaka
• Biaou, Carlos
• Wu, Junqiao
• Dubon, Oscar D.
• Das, Sujit

Abstract

We demonstrate the selective, pulsed-laser deposition of hexagonal GaS and monoclinic Ga₂S₃ films on sapphire substrates from a single Ga₂S₃target in high-vacuum conditions. Growth at substrate temperatures below 550 °C causes GaS film formation, which indicates non-stoichiometric transfer from the target to the film. Surprisingly, stoichiometric transfer occurs at substrate temperatures above 650 °C with monoclinic Ga₂S₃ as the preferred, higher S-content phase. Through a series of growth and annealing experiments, we show that GaS nucleation under S-deficient conditions leads to the preferred growth of this layered, hexagonal phase below 550 °C. Furthermore, GaS films annealed above 650 °C under high vacuum are transformed to Ga₂S₃, reflecting the greater stability of the monoclinic phase. By first growing Ga₂S₃ at a higher temperature and subsequently growing GaS at a lower temperature, we can fabricate GaS/Ga₂S₃ heterostructures in a single growth process.

Topics

• Deposition
• phase
• experiment
• layered
• annealing
• Gallium