Polarization-dependent XAFS Measurements of Spontaneous Ordering in MOCVD-Grown Ga0.5In0.5P on GaAs Substrates

Certain thin-film alloys deposited using epitaxial growth techniques have shown spontaneous long-range ordering and band gap reduction under particular growth conditions. One such thin film is Ga 0.5 In 0.5 P grown by MOCVD on single-crystal GaAs aligned 2° from the (100) axis to achieve lattice match. Quantitative results on the gallium nearest neighbor and second nearest neighbor distances, coordination number and disorder parameters will be presented and short range structural ordering will be discussed for several ordered and disordered samples. The data reported are obtained at room and liquid nitrogen temperatures using the total electron yield detection.