Abstract
Extended x-ray absorption fine structure (EXAFS) measurement is the technique to measure nondestructively the nearest-neighbor distance, to the accuracy within 0.01 Å or better, coordination number, and atomic species. Especially, fluorescence-detected EXAFS is best suited to characterize the atomic scale microstructure of epitaxially grown thin layers on a thick substrate. We have investigated the microstructure for each atomic pair of Ga-P, Ga-As, and In-As in (Ga,In)(As,P) alloys lattice-matched with InP, over a wide range of composition from dilute limit, through quaternary, to ternary. Constant atomic distances over the wide range were revealed when the average lattice parameter was kept constant.