Microstructure and homogeneity in (In,Mn)As III-V-based diluted magnetic semiconductor epitaxial films

Microstructural evaluation of thick (In,Mn)As epitaxial films grown by molecular-beam epitaxy on InAs/GaAs(100) substrates is carried out by transmission electron microscopy (TEM). Films grown at the substrate temperature of Ts=300 °C show the inclusion of MnAs crystallites in the zinc-blende host matrix, in which two types of crystallite morphologies, rod and approximately round shapes, are identified. In contrast, the MnAs crystallites are not observed in films grown at Ts=200 °C, and TEM studies confirm that the films are primarily of zinc-blende structure. Microstructural defects in the films are also discussed to assess the quality of epitaxy.