Influence of Oxygen Partial Pressure on Opto-Electrical Properties, Crystallite Size and Dislocation Density of Sn Doped In_2O_3 Nanostructures

In this research, high-quality Sn doped indium oxide (ITO) thin films were grown on glass slide substrates using an electron beam evaporation method. Vacuum chamber partial pressure was changed and the electro-optical as well as the microstructure parameters were investigated. The microstructure of prepared films was evaluated by x-ray diffraction analysis in terms of crystallite size and dislocation density. It was found that the best results [high transparency (88%) over the visible wavelength region, low sheet resistance of 12.8 Ω/square, the optical band gap of 3.76 eV, crystallite size of 49.5 nm and dislocation density of 1.42 times 10^14 m^-2] were achieved for the sample produced at a partial pressure of 1 times 10^-4 mbar. Therefore, one can successfully control the physical properties of ITO films by varying the oxygen content of the evaporation system. The correlation between the band gap and carrier concentration in addition to the average crystallite size of films was also established.