Characterization of CdS_xTe_1-xthin films through thermoelectric power measurements

Abstract

Polycrystalline CdSxTe1-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 CdSxTe1-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 CdSxTe1-x films.

Properties of the CdSxTe1-x solid solution: As a single product and as a part of the CdS/CdTe solar cell

“…Polycrystalline CdSxTe1-x and CdS1-yTey thin films can be produced by several methods such as: thermal evaporation (co-evaporation of CdS and CdTe) [7][8][9], RF magnetron sputtering [9], brush plating [10], pulsed laser deposition [11], pulse plating [12], closed space sublimation [13][14][15][16][17], metal organic chemical vapor deposition MOCVD [18], chemical bath deposition (CBD) [19], and spray pyrolysis [20][21][22] by first producing CdS films then annealing in Te atmosphere. It is well known that the properties of produced films are affected by the deposition technique and deposition parameters used, such as deposition rate, substrate temperature, and thickness of the films [8].…”