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 showed that a weak ordering effect still exists in SSMBE grown epilayers with tilted substrates. However, the ordering effect can be drastically reduced by growing In0.5Ga0.5P on a 15 degrees tilted substrate with an InAlP/InGaP superlattices (SL) buffer layer. The In0.5Ga0.5P epilayer grown by this method showed a peak photoluminescence (PL) energy of similar to 1.91 eV at room temperature, which is similar to the reported value for a fully disordered sample. The intensity of the ordering effect is characterized by polarized PL spectroscopy, and the reduction in the ordering intensity is attributed to the elimination of initial surface strain by the SL buffer layer.