Electrical resistivity of vacuum-deposited and vacuum-annealed P-Ag, Se thin films of thicknesses 0 between 600 and 2000 A has been measured in vacuum. It is found that all the films exhibit semiconducting behavior and the energy band gap is a function of thickness increasing linearly with it. It is also found that the film resistivity and temperature coefficient of resistivity (TCR) are both functions of inverse thickness as expected from the thin-film size-effect theories. The linear dependence of the band gap on thickness is thought to be due to the large density of dislocations in thin films and its variation with thickness and the changing stoichiometry of the films. The reciprocal thickness dependence of resistivity and TCR is explained by the effective mean-free-path models. 0 The mean free path l~e stimated from this model turns out to be about 1300 A and the value estimated from the p plot agrees well with that estimated from the P plot. Also, carrier concentration in the films is estimated to be about 6X 10" cm

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Crystalline Sb2Te3 thin films of different thicknesses have been prepared by subsequent annealing (at 500 K) of vacuum deposited, as-grown, amorphous thin films of Sb2Te3 prepared on glass substrates at room temperature. Thermoelectric power and electrical resistivity of these annealed (crystalline) films have been determined as a function of temperature. The size dependence of thermoelectric power and electrical resistivity have been analyzed by the effective mean free path model of size effect. It is found that both the thermoelectric power and the electrical resistivity are linear functions of the reciprocal of thickness of the films. The data from the analyses of thermoelectric power and electrical resistivity have been combined to evaluate important material parameters such as carrier concentration, their mean free path, Fermi energy, and effective mass. The values of some of these are compared with the previous available values from literature.

Indium oxide thin films have been prepared by thermal oxidation of vacuum-deposited indium thin films in air in an open furnace at about 600 K. These indium oxide thin films prepared by thermal oxidation have been examined for optical transparency by measuring their optical absorbance as a function of wavelength. From the optical absorption data, optical band gap and the nature of the forbidden energy gap in the indium oxide thin films have been determined. Electrical conductivity measurements have also been carried out on the above oxide films as a function of temperature during heating and cooling cycles in vacuum. It is found that after the first heating, electrical conductivity increases to a significant extent due to removal of point defect clusters due to annealing which contribute to both carrier generation and scattering. From the thermoelectric power measurements carried out, it has been concluded that electrons are the majority carriers in these indium oxide thin films.

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