X-ray rocking curve characterization of ZnTe layers grown on GaAs by hot-wall epitaxy

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Abstract
The influence of the (100) GaAs substrate preheating process on the crystalline quality of ZnTe epilayers grown by hot-wall epitaxy has been investigated. For preheating temperatures higher than 560 degrees C and preheating times longer than 15 min, all layers were monocrystalline and grew in the (100) direction. The FWHM of the X-ray rocking curves were measured as a function of the preheating temperature and showed a minimum of 107 arcsec around 600 degrees C. The dependence of the FWHM on the ZnTe layer thickness has also been determined. It decreases from 800 arcsec to 200 arcsec for an increase in the layer thickness from 1 to 5 mu m and saturates at 100 arcsec for layers thicker than 6 mu m. The layers showed an excellent homogeneity with a variation of 2% in the FWHM measured in different spots along the layer diagonal. The surface morphology was mirror-like and showed elongated textures. The resistivity of the layers at room temperature was 5*102 Omega cm.