Ultra-microtome techniques were used to prepare thin cross-sections of a (111) CdTe epilayer, which had been deposited onto a (100) GaAs substrate by using metalorganic chemical vapor deposition. The structure of the samples was investigated by means of high-resolution transmission electron microscopic diffraction contrast techniques. The polarity of the (111) layers was deduced from convergent beam electron diffraction and characteristic X-ray emissions under various electron channelling conditions. Rutherford back-scattering and channelling experiments which were performed on the bulk film confirmed the presence of a multiply-twinned lamellar structure, as observed using electron beam techniques. The observation of strong channelling confirmed that the crystallinity was good, and that no significant concentration of defects occurred. High-resolution transmission electron microscopic images of the (111)-type epilayers from interfaces across lamellar twins revealed few dislocations or crystal defects. The diffraction contrast images indicated the presence of a periodic strain, in the GaAs, which was parallel to the interface. Other results confirmed that the layer was of B-type, and that the lamellar twins did not invert the phase.

S.R.Glanvill, C.J.Rossouw, M.S.Kwietniak, G.N.Pain, T.Warminski, L.S.Wielunski: Journal of Applied Physics, 1989, 66[2], 619-24