The influence of post-annealing treatment on the electrical properties of In2O3 thin films prepared by an ultrasonic spray CVD process

Indium oxide thin films were deposited on glass substrates at different temperatures between 623 and 773 K, by an ultrasonic spray chemical vapor deposition process. The aerosol containing the precursors of the films (InCl3·4H2O) was transported to the reaction zone, using N2 as carrier gas. X-ray diffraction studies showed that films are polycrystalline in nature. Typically, films as-deposited have a minimum resistivity of 2.2×10−3 Ω cm and an optical transmission >85%. After deposition these films were subjected to many cycles of heating–cooling in air (between 300–450 K and 300–673 K). During the first one or two cycles, the maximal heating temperature was approximately 450 K, and for the following was approximately 673 K. The percentage gain in electrical conductivity after the first cycle was calculated and discussed in function of the temperature deposition of films. The activation energies were calculated.