Structural and electronic properties of indium-tin-oxide sol-gel films for various post-annealing treatment

We investigated the change in the electronic properties of indium-tin-oxide sol-gel thin films for various annealing temperatures ( T anneal ) up to 800 °C. The X-ray diffraction (XRD) measurement showed that the crystallinity was enhanced continuously with increasing T anneal . From the electrodynamic analysis performed by using spectroscopic ellipsometry, in accord with the XRD result, the charge carrier density of the films was found to increase, and resultantly the DC conductivity was found to increase with thermal annealing at a higher T anneal . The optical absorption in the visible region was rather sizable in relation to the quite broad feature of the interband transition near 4 eV. This implies that high-temperature thermal annealing may induce some defects inside the film. Our findings for the thermally-annealed sol-gel films are compared with the optical properties of the photo-annealed sol-gel film and the commercially-used film fabricated by using a sputtering technique.