Chemical ordering in GaxIn1−xP semiconductor alloy grown by metalorganic vapor phase epitaxy

GaInP films grown by metalorganic vapor phase epitaxy on GaAs substrates are observed by transmission electron microscopy in cross sections. A 1/2 (111) (CuPt type) ordering is observed, for the first time in this system, with only two orientation variants occurring. A layered structure (layer thickness 2 nm) develops parallel to the substrate and extra diffuse scattering is also observed at 2/9 (220). The observation of the 1/2 (111) ordering is not predicted by the current first-principle phase diagram calculations. Substrate effects on the orientation and number of ordering variants are identified.