Characterization of CdS_xTe_1-x thin films through thermoelectric power measurements

Polycrystalline CdS_xTe_1-x thin films deposited using a novel procedure based on the close spaced sublimation (CSS) method were characterized through thermoelectric power (α) measurements. The results revealed that these types of compounds present mixed conductivity and that their net conductivity becomes n-type for S concentrations greater than 50% (x>0.5) and p-type when the S content is less than 50%.

The results were interpreted with the help of theoretical calculations of α versus T, carried out using a model which includes scattering processes inside the grain and in the grain boundaries as well as dimensional effects. Comparing experimental values of α versus T with the theoretical calculation, it was found that the electrical transport in the CdS_xTe_1-x thin films is mainly affected by the interaction of electrons and holes with acoustic phonons and by scattering processes in the intergrain regions. The surface and bulk thermal conductivity also influence the electrical transport of the CdS_xTe_1-x films.