Characterization of CdSxTe1-x thin films through thermoelectric power measurements

Polycrystalline CdSxTe1-x thin films deposited using a novel procedure base d on the close spaced sublimation (CSS) method were characterized through t hermoelectric power (alpha) measurements. The results revealed that these t ypes of compounds present mixed conductivity and that their net conductivit y 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 a lpha versus T, carried out using a model which includes scattering processe s inside the grain and in the grain boundaries as well as dimensional effec ts. Comparing experimental values of alpha versus T with the theoretical ca lculation. it was found that the electrical transport in the CdSxTe1-x thin films is mainly affected by the interaction of electrons and holes with ac oustic phonons and by scattering processes in the intergrain regions. The s urface and bulk thermal conductivity also influence the electrical transpor t of the CdSxTe1-x films.