Coexistence of the Cu3Au type ordered structure and the fine modulation in CdxZn1-xTe epilayers grown on GaAs substrates

Abstract

Selected-area electron diffraction pattern (SADP) and transmission electron microscopy (TEM) measurements were carried out to investigate the spontaneously ordered structure in CdxZn1-xTe epitaxial layers grown on (001) GaAs substrates. The SADP showed superstructure reflections with symmetrical intensity, and the high-resolution TEM (HRTEM) image showed doublet periodicity in the contrast of the {100} and {110} lattice planes. The results of the SADP and HRTEM measurements showed that Cu3Au type ordered structures were formed in the CdxZn1-xTe epitaxial layers. The dark-field TEM image showed that the size of the Cu3Au type ordered domains with a rectangular-like shape was approximately 15similar to30 nm thick, with widths ranging from 30 to 200 nm. Fine modulations in the ordered domains were also observed. These results provide important information on the microstructural properties for enhancing the efficiencies of CdxZn1-xTe-based optoelectronic devices operating at the blue-green region of the spectrum. (C) 2002 American Institute of Physics.