Selective growth of σ- Al2O3 nanowires and nanobelts

We report the selective growth of σ- Al2O3 nanowires and nanobelts via a catalyst-free chemical vapor deposition process under ambient pressure. By controlling the flow rates of the carrier gas, high-yield production of uniform alumina nanowires with diameter distribution (100nm-200nm) was achieved at a high growth rate over 200 μm/hour. Alumina nanobelts with variable width were also synthesized by modulating the carrier gas purge process. Further, the effects of temperatures and carrier gas flow rates on the growth of alumina nanostructures were also investigated. Oxygen partial pressure and supersaturation level of the aluminum suboxide are thought to be important factors in the formation process of the alumina nanowires or nanobelts. The typical growth of the alumina nanowires and nanobelts can be ascribed to vapor-solid (VS) mechanism. Copyright © 2008.