Atomic-scale structure of Ga1-x Inx P alloys measured with extended x-ray absorption fine structure spectroscopy

Extended x-ray absorption fine structure spectroscopy was used to measure the interatomic distance distributions of the first three nearest-neighbor (NN) shells around Ga and In atoms in Ga1-x Inx P. The first NN shell has a composition-dependent bimodal distance distribution with a relaxation parameter of =0.80±0.04 similar to other III-V ternary alloys. The second NN shell distance distribution remains multimodal, corresponding to the three different cation-cation pairs but is closer to the virtual-crystal approximation (VCA). The third NN shell mean distance is well approximated by the VCA although the distribution is significantly broadened. Predictive model calculations are discussed in detail where good agreement with experimental results is found. Like in Ga1-x Inx As, lattice mismatch is accommodated in Ga1-x Inx P by both bond-length and bond-angle relaxations although primarily via the latter.