Effects of ambient high-temperature annealing on microstructure, elemental composition, optical and electrical properties of indium tin oxide films

Abstract

500 nm-thickness indium tin oxide (ITO) films were deposited onto quartz glass substrates and annealed at 700–1000 °C for 1 h. Microstructure, elemental composition, optical and electrical properties of ITO films were systematically studied. It is found that the crystalline is cubic bixbyite, and preferred orientation changes from mainly (222) to (400) with the increasing temperature. Obvious changes are also observed in morphology of ITO films during the ambient high-temperature annealing. ITO film annealed up to 1000 °C is still stable Sn doped In2O3, oxygen defects decreases and adsorbed oxygen increases. The resistivity of ITO films after annealed at 700 and 800 °C firstly increases slightly and then increases sharply, when annealing temperature is increased to 900 and 1000 °C. Average transmittance of these films was 70%–80% and their optical band gap shifts to lower energy with the increase of the annealing temperature.