Investigation of mechanical properties of transparent conducting oxide thin films

We present an analysis of the mechanical properties of transparent conducting oxide (TCO), indium tin oxide (ITO) and indium zinc oxide (IZO) thin films on the glass substrates. The thin films of ITO and IZO were deposited by radio frequency magnetron sputtering at a low processing temperature. The elastic modulus and hardness of the TCO films prepared at different deposition conditions are determined by nano-indentation experiments. The results show that the presence of hydrogen in a gas mixture during film deposition could vary significantly the hardness and elastic modulus of the ITO films. However, the hardness and elastic modulus of IZO films prepared at the similar conditions are found to be less sensitive to the hydrogen used in the film deposition. The correlation between elastic moduli and the porosity in ceramic materials is used to determine the porosity of the TCO films thus prepared. It is found that the porosity of the ITO films can be changed approximately by 9%, when the films are prepared in the presence of hydrogen in the gas mixture.