Synthesis and characterization of indium tin oxide (ITO) nanoparticle using gas evaporation process

In this paper, indium tin oxide (ITO) nanoparticle was synthesized by gas evaporation process, and its physical properties such as particle size, specific surface area, crystal structure, and composition ratio according to the heat-treating conditions were investigated to optimize them. The source material was charged in a chamber with vacuum circumstance of 1x10(-5) torr, and the oxygen gas was supplied during evaporation. The InxOySnOz nanoparticle was synthesized, and the nanoparticle was heat-treated to have optimal point of particle size, crystal structure, and composition, etc. The synthesized nanoparticle was heat-treated with controlling such parameters as heat-treating temperature and environmental gas. Particle size, specific surface area, crystal structure, and concentration ratio of the synthesized ITO nanoparticle by using the method were analyzed with high resolution transmission electron microscopy (HRTEM), BET surface area analyzer, X-ray diffraction (XRD), and energy dispersion spectroscopy (EDS). As a result, in case of ITO nanoparticle synthesized at 300 degrees C, its mean particle size is 5 nm and the surface area exceeds 100 m(2)/g. The XRD analysis indicates that the crystal structure of the particle is cubic one with orientation of (222), (400), (440). Also, the EDS analysis demonstrates that the concentration ratio of indium and tin is 91 at% and 9 at% in the lattice of the ITO nanoparticle. Since the lower sized ITO nanoparticle produces the ITO sputtering target with higher density and the ITO sputtering target with higher density makes the high quality ITO electrode, the synthetic condition of 300 degrees C is considered to be optimal condition for enhancing the high quality ITO electrode.