Improvement of Structural, Electrical, and Optical Properties of Sol–Gel-Derived Indium–Tin-Oxide Films by High Efficiency Microwave Irradiation

Abstract

Herein, indium–tin-oxide (ITO) thin films are prepared by a solution-based spin-coating process followed by a heat-treatment process with microwave irradiation (MWI). The structural, electrical and optical properties of the films are investigated. The properties of the microwave-irradiated sol–gel ITO films are compared with those of as-spun ITO films and sol–gel ITO films subjected to conventional furnace annealing (CFA) or a rapid thermal process (RTP). After microwave irradiation, the sol–gel ITO thin films are found to have crystallized, and they indicate enhanced conductivity and transparency. Furthermore, the resistances of the ITO films are decreased considerably at increased microwave power levels, and the resistivity of the films almost saturate even at a low microwave power of 500 W. The improved physical properties of the MW-irradiated samples are mainly due to the increase in the electron concentration of the ITO films and the increase in the carrier mobility after MWI.