THE ELECTRICAL-PROPERTIES OF CDTE-FILMS OF DIFFERENT PREPARATION CONDITIONS IN CORRELATION WITH MICROSTRUCTURE CHANGES

Polycrystalline films of CdTe have been thermally deposited on glass s ubstrates. Using the Van der Pauw technique, the dark resistivities ha ve been measured at different temperatures (298-523 K). The resistivit y, rho, was found to decrease markedly in the range of thickness less than 400 nm and was then subjected to a slight decrease at larger thic knesses. The behaviour was found to fit properly with the Fuchs and So ndheimer relation with parameters rho = 4.39 x 10(5) Omega cm and mean free path, I = 734 nm. Raising the substrate temperature and decreasi ng the deposition rate were found to increase the resistivity monotoni cally. Annealing the prepared films caused a significant decrease in t he resistivity particularly for films of small thicknesses (t < 500 nm ). The log rho vs. 1/T curves showed three distinct regions at high, l ow and sufficiently low temperature regions with decreasing activation energies, 0.39 eV, 0.29 eV and 0.19 eV respectively. The data obtaine d at higher regions has been analysed in accordance with Seto model. A ttribution of the film resistivity variation to microstructure changes of the films are discussed.