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temperature. The CdTe source and the substrate are separated by a smal! distance and the source is maintained at a higher temperature than the substrate.The CdTe dissociates into its elements (2CdTe(s) + 2Cd(g) + Te2(g) ) which recombine on the substrate surface, to form the CdTe film The apparatus developed for the deposition of CdTe films by the CSS technique is shown in Fig. 1. The most significant characteristics of CdTe polycrystalline thin films were grown using a new procedure based on the C.S.S. Technique. With an adequate control of the deposition parameters, it was possible to grow CdTe films with grain sizes greater than 45 pm. The samples were characterized by XRD, SEM and EDS measurements. The studies revealed that the substrate and sublimation temperatures influence strongly the crystallographic orientation of the films, which grow with a mixed structure of cubic and hexagonal phases. EDS analysis carried out on different samples, showed a significant iinfluence of some deposition parameters on the chemical composition of the CdTe films.The effect of introducing 0 2 during the deposition of the CdTe films, on the resistivity and crystallographic properties will also be discussed.

A new procedure to realize low resistance contact to polycrystalline CdTe thin films deposited by CSS method will be presented. Initially, the CdTe samples are etched with an oxidant agent in order to form a Te-rich surface layer; subsequently the CdTe samples are dipped in a CuCl solution to form a p+ -CuxTe (15x52) layer through an ion -exchange chemical reaction; finally, the samples were contacted with Cu and Cu/Au deposited by thermal evaporation and C:Cu deposited by DC magnetron sputtering. Contact resistivities of 0.16 Rcm2 were obtained using sulphochromic solution as oxidant agent and Cu as electrical contact. The changes induced in the CdTe-surface by the different surface treatments were studied by means of XRD, and AES measurements.

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