Preparation of optically transparent and conducting radio-frequency sputtered indium tin oxide ultrathin films

Abstract

Highly conducting and optically transparent indium tin oxide (ITO) ultrathin films (thickness < 100 nm) are needed in order to improve the performance of optoelectronic devices, especially for plasmonic enhanced photovoltaic devices. ITO thin films (thickness ~ 60 nm) are deposited on glass substrates at room temperature by radio-frequency magnetron sputtering with a power of 200 W under argon atmosphere followed by rapid thermal annealing for 1 min at various temperatures in nitrogen environment. The effect of rapid thermal annealing on the physical and chemical changes of the ITO thin films is explored and co-related the changes with optoelectronic properties of the films as well. As-deposited thin films after rapid thermal annealing at 600°C display significant changes in the microstructure with occurrence of crystallites (average crystallite size ~ 11.9 nm), average optical transmittance (~ 88.2%) in the visible region, and electrical resistivity as low as 1.09 × 10−4 Ω-cm with high figure of merit of 2.27 × 10−2 Ω−1 — indicating their suitability as transparent conducting anode for the relevant electronics.