Mn-Promoted Growth of Mg-Based Spinel and Pyroxene Nanostructures

In this work, we demonstrate Mn-promoted growth of oxide nanostructures standing on a single-crystal MgAl2O4 substrate after heat treatment. Unlike the short truncated spinel pyramids under Au seeds, the addition of Mn produces spinel nanopillars with lengths of 100–300 nm and pyroxene nanowires up to 10 μm. Compared to Au seeds, Au/Mn seeds have different adsorption behavior and therefore provide an additional mass transfer path along seed surfaces that promotes the growth of nanostructures. This vaporization approach has a potential of being applicable to a wide range of complicated oxides.