Direct synthesis of single crystalline In2O3 nanopyramids and nanocolumns and their photoluminescence properties

Single crystalline indium oxide pyramid and column structures were synthesized by a simple physical evaporation technique. The pyramid structure was obtained without any catalytic action while the column structure was produced using gold as the catalyst. The nanostructures were characterized by x-ray diffraction, scanning electron microscopy and transmission electron microscopy. A blue-green photoluminescence band in the visible region was observed in the In2O3 structures which could be ascribed to the existence of a large amount of singly ionized oxygen vacancies, confirmed by electron paramagnetic resonance.