In2O3 nanocones have been in situ grown on the surface of indium substrates by heating indium grains coated with Au films in 850～1000 ℃ under the flow of O2. The controllable synthesis of In2O3 nanocones with different diameters was achieved by adjusting the heating temperature. The as-synthesized products were characterized by means of Raman spectra, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results show that the In2O3 nanocones are of single crystalline phase with a body-center cubic structure and have a controllable diameter and length in the range of 0.1～0.6 and 0.2～2.9 μm, respectively. A possible mechanism was also proposed to account for the formation of the In2O3 nanocones. A strong blue photoluminescence with peaks at 416 and 439 nm was observed in the In2O3 nanocones at room temperature. The 416 and 439 nm blue emission was attributed to radiative recombination between an electron on an oxygen vacancy and a hole on an indium-oxygen vacancy center in the In2O3 nanocones.

Key words: In2O3, nanocone, in situ thermal oxidation route, photoluminescence