ORDERING REDUCTION IN IN0.5GA0.5P GROWN BY SOLID SOURCE MOLECULAR-BEAM EPITAXY

In0.5Ga0.5P grown on GaAs substrates with different tilting angles by solid source molecular beam epitaxy (SSMBE) is studied. The results sh owed that a weak ordering effect still exists in SSMBE grown epilayers with tilted substrates. However, the ordering effect can be drastical ly reduced by growing In0.5Ga0.5P on a 15 degrees tilted substrate wit h an InAlP/InGaP superlattices (SL) buffer layer. The In0.5Ga0.5P epil ayer grown by this method showed a peak photoluminescence (PL) energy of similar to 1.91 eV at room temperature, which is similar to the rep orted value for a fully disordered sample. The intensity of the orderi ng effect is characterized by polarized PL spectroscopy, and the reduc tion in the ordering intensity is attributed to the elimination of ini tial surface strain by the SL buffer layer.