Molecular beam epitaxy and polarized excitonic emission of layered GaTe/GaAs thin films

Abstract

This paper reports on molecular beam epitaxy of GaTe thin films grown on GaAs(0 0 1) and GaAs(1 1 1)B substrates at temperatures of TS = 450–550 °C under weak Te-rich conditions (Te/Ga ≈ 10–18) as well as studies of their structural and optical properties. The results obtained by transmission electron microscopy and X-ray diffraction techniques have established a correlation between the growth conditions and the GaTe polymorphic transition from hexagonal to monoclinic phase. The critical temperature of the polymorphic transition was found to be ∼540–550 °C. The monoclinic GaTe layers demonstrate an excellent excitonic emission that was confirmed by both micro-photoluminescence and time-resolved photoluminescence techniques. The strong anisotropy of the GaTe excitonic emission has been demonstrated.