Growth and Properties of Self-Aligned MgO Nanowires

A simple VLS route was used to produce self-aligned MgO nanowires on both polished crystalline (c-axis sapphire) and ceramic (alumina) surfaces. Growth on alumina produces vertically-aligned, very thin nanowires, indicating enhanced growth at the liquid-solid interface. Growth on polished sapphire results in faceted MgO nanowires which are perpendicular to the $r$-plane of sapphire and show evidence of competing vapor-solid growth mechanism. The difference in the morphology and structure of the nanowires grown using the two different substrates clearly illustrates the affect of substrate on the growth process. \textit{This work was partially supported by DARPA, by the Department of Homeland Security, and by the National Science Foundation.}