In this paper, we present a comparative study of photoluminescence and its relation to the structural properties of cadmium sulphide (CdS) thin films grown by chemical bath deposition (CBD), close spaced vapour transport, laser ablation (LA) and sputtering. Taking into account that the physical properties of CdS thin films depend upon the growth technique and the optimization of the deposition conditions for each technique, we show that the best crystal perfection occurs for LA-CdS films since the main photoluminescence peak at low temperature is due to bound excitons (2.53 eV). As expected, the films with the worst crystalline quality are those grown by CBD, ascertained by the photoluminescence band around 1.72 eV due to sulfur vacancies ('red band') without the corresponding exciton band. The photoluminescence results are correlated to x-ray diffraction measurements that confirm the above results.

Alternative procedure for the fabrication of close-spaced sublimated CdTe solar cells CdTe thin films deposited by close space vapor transport ͑CSVT͒ under variable growth conditions and postthermal and chemical treatments were studied by means of photoconductivity measurements in the temperature range of 90-300 K. The influences of the deposition temperature gradient, the oxygen content in the growth chamber, and the CdCl 2 treatment and chemical etching upon the intergrain barrier height of CSVT polycrystalline CdTe thin films were determined. The grain boundary barrier height (E b ) as a function of the intensity of the incident light was analyzed, and values of E b under illumination of 100 mW/cm 2 ͑AM1͒ were obtained in each case. These results are important for improving CdS/CdTe solar cell performance in the near future.

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Structural, morphological and optical properties of CdS films, deposited by the pulsed laser ablation technique on SnO2:F/glass substrates, were studied as a function of time deposition. Up to our knowledge the properties of these films grown onto conducting polycrystalline substrates have not been reported before. The photoluminescence measurements showed the existence of an exciton peak at room temperature, as an indication of good crystalline quality of the layers. A thermal treatment was applied to the samples in a 100 mT Ar atmosphere at 400 °C for 30 min after the deposition of a CdCl2 layer on them. Films characterization was carried out through X‐ray diffraction, photoluminescence and atomic force microscopy measurements. The structural, optical and morphological properties as a function of growth parameters are presented and discussed. Thermal treatment makes uniform the grain size in the samples, with a tendency to increase the grain size average. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)