Hg1-xCdxTe (MCT) was grown by hot wall epitaxy. Prior to the MCT growth, the CdTe (1 1 1) buffer layer was grown on the GaAs substrate at the temperature of 590degreesC for 15 min. When the thickness of the CdTe buffer layer was 5 (mm or even thicker, the full-width at half-maximum values obtained from the X-ray rocking curves were found to significantly decrease. After a good quality CdTe buffer layer was grown, the MCT epilayers were grown on the CdTe(1 1 1)/GaAs substrate at various temperatures in situ. The crystal quality for those epilayers was investigated by means of the X-ray rocking curves and the photocurrent experiment. The photoconductor characterization for the epilayers was also measured. The energy band gap of MCT was determined from the photocurrent measurement and their composition rates from the temperature dependence of the energy band gap were also obtained. (C) 2002 Elsevier Science B.V. All rights reserved.