Self-catalytic growth of indium oxide flower-like nanostructures by nano-cluster deposition (NCD) at low temperature

Flower-shaped indium oxide nanostructures were grown at a low temperature (250 [degree]C) on Si (100) substrates by NCD technique without using metal catalyst. Bud shaped leaf like structures are obtained with lengths and diameters in the range of 150-250 nm and 75-125 nm, respectively, which are compacted into a flower-shaped structure. Transmission electron microscopy and selected area electron diffraction patterns taken on the leaf-like structure show crystalline cubic phase, with preferential orientation along (222) and (400) directions. The composition of indium and oxygen was confirmed from XPS analysis. The room temperature photoluminescence (PL) spectrum of flower-like In2O3 nanostructure shows a blue emission centered around 428 nm under the 383 nm UV excitation, which is mainly attributed to the oxygen vacancy in the In2O3 nano/microstructures. A growth model for the formation mechanism of the self-catalytic growth of flower shaped structure is proposed.