Long-range order in CdxZn1-xTe epilayers grown on GaAs substrates

Selected area electron diffraction pattern (SADP) and transmission electron microscopy (TEM) measurements were carried out to investigate the ordered structure in CdxZn1-xTe epitaxial layers grown on (001)GaAs substrates. The SADP showed two sets of superstructure reflections with symmetrical intens ity, and the high-resolution TEM (HRTEM) image showed doublet periodicity i n the contrast of the (111) lattice planes. The results of the SADP and HRT EM measurements showed that CuPt-type ordered structures with two different variants were observed in the CdxZn1-xTe epitaxial layers. The formation o f a CuPt-type ordered structure in the CdxZn1-xTe epitaxial layer might ori ginate from the minimization of strain relaxation energy in the reconstruct ed GaAs(001) surface. A possible atomic crystal structure for the CdxZn1-xT e epitaxial layer is presented based on the HRTEM results. These results pr ovide important information on the microstructural properties for enhancing device efficiencies of operating at the blue-green region of the spectrum. (C) 2001 Elsevier Science B.V. All rights reserved.