High-pressure photoluminescence study of ordered Ga0.5In0.5P alloys grown on GaAs by organometallic vapor phase epitaxy

Photoluminescence (PL) measurements on Ga0.5In0.5P grown by organometallic vapor phase epitaxy on GaAs substrates at various growth temperatures have been made as a function of pressure up to about 4.5 GPa. In the pressure range 0–3.8 GPa the PL spectrum exhibits a shift to higher energies. It is found that the pressure coefficient of the PL peak energy depends significantly on the growth temperature and hence on the degree of ordering. These results are partly explained in terms of repulsion between the Γ-folded energy states in the CuPt-type ordered structure.