CVT and PVT growth and characterization of GaS crystals

Gallium sulphide (GaS) has been prepared by chemical vapour transport (CVT) and physical vapour transport (PVT). The obtained crystals show two different morphologies: large layers and little microstructures respectively, both indicated hexagonal crystal structure. Energy-dispersive X-ray spectroscopy (EDX) measurements confirm the correct stoichiometry; the hexagonal structure has been confirmed with x-ray analysis and transmission electron observations (TEM). Optical study by cathodoluminescence shows direct bandgap with energy gap at 2.5 eV for both samples.