Disordering of the ordered structure in metalorganic chemical vapor deposition grown Ga0.5In0.5P on (001) GaAs substrates by zinc diffusion

Transmission electron microscopy is used to study sublattice atomic ordering in as‐grown and Zn‐diffused epitaxial layers of Ga0.5In0.5P that are grown lattice matched to GaAs by low‐pressure metalorganic chemical vapor deposition. The as‐grown Ga0.5In0.5P layers exhibit an ordered trigonal structure with In‐Ga ordering occurring on only two sets of {111} planes. After a Zndiffusion is performed at 650 °C, the ordered structure is no longer observed in selected area diffraction patterns. Simultaneously, the room‐temperature photoluminescence peak shifts by ≊90 meV to higher energy, as compared to the undiffused samples. These data provide direct experimental evidence that Ga0.5In0.5P with an ordered distribution of Ga and In atoms on the column III sublattice can be converted to a random alloy by Zndiffusion