Effects of annealing temperature on nanomechanical and microstructural properties of Cu-doped In2O3 thin films

In this study, the effects of post-annealing on the microstructural, surface morphological and nanomechanical properties of Cu-doped In 2 O 3 (CIO) thin films were investigated using X-ray diffraction, scanning electron microscopy and nanoindentation techniques, respectively. The CIO thin films were deposited on the c -plane sapphire substrates at room temperature using the radio frequency magnetron sputtering system. Post-annealing was carried out at the temperatures of 750–950 °C, and resulted in progressive increase in the average grain size and improved crystallinity of CIO thin films. In addition, the hardness and Young’s modulus of CIO thin films were measured by a nanoindenter equipped with a Berkovich diamond tip and operated with the continuous contact stiffness measurements mode. Results indicated that the values of hardness and Young’s modulus of CIO thin films increased when the annealing temperature increased from 750 to 950 °C.