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In this work, CdTe(0 0 1) and CdTe(1 1 1) single-crystal films were successfully grown on GaAs(0 0 1) substrates by molecular beam epitaxy. By changing the nucleation temperature, CdTe(0 0 1) and (1 1 1) films could be controllably grown on the GaAs(0 0 1) substrates. The CdTe(0 0 1) and (1 1 1) films were grown via low-temperature nucleation followed by high-temperature growth. To optimize the quality of CdTe(0 0 1) films, a CdTe/ZnTe superlattice was used to reduce the lattice mismatch, and the CdTe(0 0 1) film was grown under a cadmium-rich atmosphere. The average surface roughness of the CdTe(1 1 1) and CdTe(0 0 1) films produced was approximately 0.76 nm and 1.37 nm, respectively. The epitaxial relationship between the CdTe(1 1 1) film and the GaAs(0 0 1) substrate was studied based on X-ray diffraction pole figures. The crystal quality of the CdTe(1 1 1) film was also characterized by X-ray diffraction and etch pit density. Finally, photoluminescence spectroscopy was used to investigate the crystal quality of CdTe(0 0 1) and (1 1 1). When the CdTe(0 0 1) film was grown under a cadmium atmosphere and using ZnTe as a buffer layer, the X-ray diffraction peak around 1.56 eV disappeared; this can be related to cadmium vacancies.

Atomic force microscopy (AFM) measurements of nanometer-sized islands formed by 2 monolayers of InAs by molecular beam epitaxy have been carried out and the scan line of individual islands was extracted from raw AFM data for investigation. It is found that the base widths of nanometer-sized islands obtained by AFM are not reliable due to the finite size and shape of the contacting probe. A simple model is proposed to analyze the deviation of the measured value From the real value of the base width of InAs islands. (C) 1998 Elsevier Science B.V. All rights reserved.