Influence of Te inclusions and precipitates on the crystalline and thermal properties of CdTe single crystals

CdTe crystals grown by the Bridgman method were characterized by relating the Te excess to the bulk and their crystalline quality (CQ). The thermal diffusivity of these samples was measured using photoacoustic spectroscopy (PA). X-ray diffraction (XRD) data of the (1 1 1) peak of CdTe was employed to calculate the full-width at half-maximum (FWHM) and the lattice parameter. These results were used to compare CQ of different CdTe samples. The presence of Te inclusions and precipitates in the crystal was evident by XRD measurements and was confirmed using micro-Raman (mu R) spectroscopy. mu R microprobe scanning images were employed to determine the size, morphology, position and density of Te aggregates in the crystals. Photoluminescence (PL) measurements were carried out in order to assess the optical quality of the crystals and to relate these results to the XRD data. According to the experimental data, thermal diffusivity (alpha) is higher in samples with high crystalline quality and has strong dependence on the micro-structural composition of Te precipitates and inclusions. (C) 2000 Elsevier Science B.V. All rights reserved.