Experimental studies of the effects of atomic ordering in epitaxial Ga$_{x}$In$_{1-x}$P on their optical properties

The properties of epitaxial Ga$_{x}$In$_{1-x}$P alloys with an ordered arrangement of atoms in the crystal lattice are studied by a number of spectroscopic methods. The alloys are grown by metal-organic chemical vapor deposition onto single-crystal GaAs(100) substrates. It is shown that, under conditions of the coherent growth of an ordered Ga$_{x}$In$_{1-x}$P alloy on a GaAs(100) substrate, atomic ordering results in radical modifications of the optical properties of the semiconductor compared to the properties of disordered alloys. Among these modifications are a decrease in the band gap and an increase in the luminescence intensity. From the data of dispersion analysis of the infrared dispersion spectra and from ultraviolet spectroscopy data obtained in the transmittance–reflection mode of measurements, the basic optical characteristics, specifically, the dispersion of the refractive index and the high-frequency permittivity of Ga$_{x}$In$_{1-x}$P alloys with ordering are determined. All of the experimental data are in good agreement with the developed theoretical concepts.