Low temperature growth of high quality CdTe polycrystalline layers

We have investigated the growth of CdTe thin films on glass substrates by hot wall epitaxy. The layers have been characterized by scanning electron microscopy, atomic force microscopy, profilometry, x-ray diffraction and optical transmission. The grown samples are polycrystalline with a high preferential [1 1 1] orientation. Atomic force microscopy and scanning electron microscopy reveal pyramidal grain shapes with a size of around 0.3 mum. The surface roughness increases with sample thickness and growth temperature, reaching about 200 nm for 10 mum thick layers grown at 300 deg C. Samples with a thickness of 2 mum grown at 150 deg C showed a roughness of less than 40 nm. Optical transmission measurements demonstrate layers with high optical quality.