Investigation of the epitaxial growth mechanism of ZnTe on (001) CdTe

The first stages of the growth of highly strained ZnTe on (001) CdTe are investigated by reflection high energy electron diffraction, HRTEM (high resolution transmission electron microscopy), x-ray photoelectron spectroscopy, and x-ray double diffraction. A precise study of the factors influencing the critical thickness is presented, with emphasis on the effect of Zn pre-exposure of the CdTe surface on the subsequent ZnTe growth. Below the critical thickness small lattice distortions attributed to a nontetragonal elastic distortion are detected. An exposure of the (001)CdTe surface to a Zn flux leads to the desorption of the Cd atoms present on the top of the surface and to the formation of a c(2×2) reconstructed surface with half a monolayer of Zn on the top of the surface. Finally, the morphology of an ultrathin strained ZnTe layer embedded in a (001)CdTe matrix will be discussed using results obtained from analysis of the digitized HRTEM image.