CHARACTERIZATION OF TRANSPARENT CONDUCTING CDO FILMS DEPOSITED BY SPRAY-PYROLYSIS

Transparent conducting cadmium oxide (CdO) films have been deposited by spray pyrolysis. The film thicknesses have been determined using Rutherford backscattering spectrometry. X-ray diffraction measurements show that the films are polycrystalline with a preferential orientation along the (111) diffraction plane and the lattice parameter has been calculated. The dislocation density and strain have also been evaluated. The films possesses a transmittance of about 75% in the visible and near-infrared region. The refractive index is found to vary between 1.68 and 2.84 in the wavelength range 500-1500 nm. The values of indirect and direct bandgaps obtained are 1.98 and 2.32 eV respectively. Hall effect measurements have been carried out in the temperature range 304-349 K. Resistivity, carrier concentration and mobility of the films at room temperature have been evaluated as 6.6 x 10(-5) OMEGA m, 1.4 x 10(25) m-3 and 0.68 x 10(-2) m2 V-1 s-1 respectively. Thermoelectric power values from thermoelectric power measurements carried out in the temperature range 304-376 K have been found to be about 19.7-89 muV K-1. Laser damage studies performed at a wavelength of 1.06 mum indicate that the films possess a damage threshold density of about 2.37 x 10(4) J m-2.