Atomic oxygen irradiation resistance of transparent conductive oxide thin films

One set of tungsten-doped indium oxide thin films (In2O3:W, IWO) and another set of tin-doped indium oxide thin films (In2O3:Sn, ITO) were prepared on glass substrates by radio frequency (RF) reactive magnetron sputtering method. The as-deposited IWO and ITO films have resistivity values at a level of 10− 4 Ω
- cm. Average transmittance values of these films are above 85% in visible-light region as well as in near-infrared region. All these films were irradiated by atomic oxygen (AO) with different amount of flux in a ground-based simulation system close to the environment of low Earth orbit. Changes in characteristics including surface morphology, mechanical properties, optical and electrical properties were compared between IWO and ITO films after AO irradiation. The effects of AO irradiation on transparent conductive oxide thin films were analyzed. As a result, AO has influences on ITO and IWO thin films through the way of oxidation and erosion. Both ITO and IWO films possess suitable anti-AO properties. IWO films are more appropriate as AO protective coatings due to their compact microstructure, the coexistence of W4 + and W6 + ions in their chemical systems, and incremental WO3 protective layer under AO oxidation.