Titanium-doped indium tin oxide thin films were synthesized via a sol-gel spin coating process. Surface chemical bonding states and mechanical properties have been investigated as a function of titanium content (2 and 4 at%) and annealing temperature ranging from 400 to 600°C with increments of 100°C. Raman analysis was performed to study the phonon vibrations for the prepared samples and the results revealed the existence of ITO vibrational modes. The elemental compositions, bonding states and binding energies of the film materials were investigated using X-ray photoelectron spectroscopy (XPS) technique. The XPS results indicated that the ratio of the metallic elements (In, Sn, Ti) decreased while the oxygen ratio increased due to the increase of the oxide layer on the surface of thin films, with the incremental rise of the annealing temperature. Also, by increasing the annealing temperature up to 600°C, the Ti 2p and Cl 2p signals were no longer detected for both 2 and 4 at% Ti contents due to the thicker surface oxidation layer. Mechanical properties of the synthesized films were also evaluated using a nanoindentation process. Variations in the hardness (H) and the elastic modulus (E) were observed with different Ti at% and annealing temperatures. The hardness is within the range of 6.3-6.6 GPa and 6.7-6.8 GPa for 2 and 4 at% Ti content samples, respectively, while the elastic modulus is within the ranges of 137-143 and 139-143 GPa for 2 at% and 4 at% Ti contents samples, respectively. A combination of the highest H and E were achieved in the sample of 4% Ti content annealed at 600 °C. Furthermore, the H/E ratio ranges from 0.045 to 0.049 which reflects a reasonable level of wear resistance.
حاتم عبدالرزاق طه | Hatem Taha | 2430