Existence and atomic arrangement of the CuPt-type ordered structure near the ZnTe/GaAs heterointerface due to residual impurities

Abstract

Transmission electron microscopy (TEM) and selected area electron diffraction pattern (SADP) measurements were carried out to investigate the ordered structures near ZnTe/GaAs heterointerfaces, and Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) measurements were performed to determine the compositions of the ZnTe/GaAs interfacial layer. The SADP showed two sets of {1/2 1/2 1/2} extra spots with symmetrical intensity, and the corresponding high-resolution TEM image showed doublet periodicity in contrast of the {111} lattice planes. The results of the SADP and the high-resolution TEM measurements showed that a CuPt-type ordered (Cd, Zn)Te structure was observed near the ZnTe/GaAs heterointerface, and the AES and SIMS results showed that the ordered structure was formed due to the diffusion of Cd atoms into the ZnTe layer. Two variants, one for each direction of the doublet periodicity on the {111} lattice, were observed in the ordering, and each variant had its own domain structure with a similar probability. The formation of the CuPt-type ordered structure near the ZnTe/GaAs heterointerface originated from both the existence of the Cd residual impurities during the initial growth stage of the ZnTe epilayer and the strain relaxation of the ZnTe epilayer. These results can help to improve the understanding of the microstructural properties of the ZnTe/GaAs heterointerface. (C) 2001 American Institute of Physics.