Crystalline In2O3 nanoparticles synthesis using microwaves vaporization of metallic wires

Abstract

Single crystal In2O3 nanoparticles were synthesized using microwaves vaporization of a thin metallic In wire in air. The output of an 800 W microwave generator was coupled through an antenna to a cylindrical wave guide cavity in with a metallic In wire was placed in the electromagnetic node, where a high power density was achieved. The wire strongly absorbed the microwaves, resulting in its heating, vaporization and finally a plasma plume formation. Optical emission spectroscopy investigations indicated that a high electronic temperature was reached in the plasma plume. The vaporized material was collected on a Si wafer placed near the cavity wall. Scanning electron microscopy investigations showed that the deposited material consisted of an agglomeration of In2O3 nanoparticles. X-ray diffraction and transmission electron microscopy (TEM) investigations indicated that the nanoparticles were very crystalline, with random orientation. X-ray photoelectron spectroscopy analysis confirmed the formation of stoichiometric In2O3. High resolution TEM investigations found that the deposited nanostructures were single crystals, with faceted surfaces. This simple method could have many applications for metal nanocrystal oxides synthesis.