Synthesis and Growth of GaSe1 – xSx (x = 0–1) Crystals from Melt. Phase Composition and Properties

Vertical zone melting under argon pressure is used to grow crystals of GaSe and GaS binary compounds, as well as solid solutions in the GaSe–GaS system. The crystals of these compounds are applied in laser optics owing to a high transmission coefficient in the IR region, but they are also of a special interest in nonlinear optics, where they are used as frequency converters in the terahertz range. In this context, interest grows in alloying with isovalent and non-isovalent dopants as in a method aimed at increasing efficiency of optical frequency converters. In this work, it is shown that crystals of solid solutions are characterized by unit cell parameters which decrease linearly as the sulfur content increases. It is shown that doping of GaSe with sulfur leads to a regular shift of the edge of the transmission spectrum to the short wavelength region and to a shift of low temperature photoluminescence peaks to higher energies. Measurements of microhardness show high magnitudes depending on composition of the crystals.