Effect of hydrogen plasma treatment on transparent conducting oxides

Abstract

The effect of hydrogen plasma treatment on indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and indium-doped zinc oxide (IZO) films has been studied. X-ray photoelectron spectroscopy analysis shows that ITO and FTO surfaces get reduced to yield elemental indium and tin, respectively. Annealing of the plasma treated films in air leads to re-oxidation of the reduced surface and the electro-optical properties are recovered. In contrast, IZO films are not reduced by plasma treatment and show no changes in the electrical and optical properties. The surface of plasma treated IZO films shows a higher binding energy O(1s) peak probably due to OH or OH...O species which appear to form a protective layer against plasma degradation.