Air-annealing effects on SiO2/ITO coating

Abstract

Indium tin oxide (ITO) thin film with SiO2 protective upper layer prepared by electron beam evaporation was annealed in air up to 300°C. Evolution of transmittance, resistance and surface morphology of this SiO2/ITO coating was studied. Transmittance in visible and near-infrared range both increased while absorption edge exhibited red shift after annealing. Resistance increased monotonously with rising annealing temperature, yet increments became smaller at temperatures above 270°C. Micron-defects were observed on the surface of SiO2/ITO coating after annealing. Enhancement of crystallinity of ITO layer at high temperatures was thought to be responsible for these morphology and resistance evolutions.