A TEM microstuctural study of the factors affecting the compositional modulation in GaInAsSb/GaSb films

Quaternary semiconductor alloys based on GaSb are suitable for thermo-photo voltaic cell applications as they have low and adjustable band-gap. However, they exhibit phase separation which destroys band-gap uniformity. In this work, GaInAsSb thin films grown on GaSb vicinal substrates were studied by Transmission Electron Microscopy, in order to determine the influence of the growth parameters on phase separation. It was found that the coatings exhibit two types of compositional modulation, one parallel and the other forming an angle with the substrate plane.