Characterization of transparent conductive ITO thin films deposited on titanium dioxide film by a sol-gel process

Indium tin oxide (ITO) thin films have been deposited on titanium dioxide f ilm by a sol-gel process. The starting solution was prepared by mixing indi um chloride dissolved in acetylacetone and tin chloride dissolved in ethano l. ITO thin films containing 0-20% Sn by weight were successfully prepared by heat treatment at above 400 degreesC. The resistivity of ITO films has b een minimised by optimising the tin doping concentration in the solution. T he electrical, optical and structural properties of ITO thin films were inv estigated. The thickness of ITO films was measured by ellipsometer. The ele ctrical resistivity was measured by using the four-point probe method. The ITO thin films containing 10 wt.% Sn showed a minimum resistivity of rho = 9.5 x 10(-4) Omega cm. The spectral transmittance of ITO thin films was mea sured in the wavelength range 200-900 nm by a UV-vis spectrometer. Films wi th a thickness of 250 nm have a high transmittance of 90% at 900 nm. X-Ray diffraction measurements employing CuK alpha radiation were performed to de termine the crystallinity of the ITO films, which showed that they were pol ycrystalline with a cubic bixbyite structure. (C) 2001 Elsevier Science BN. All rights reserved.