Synthesis and characterization of Al2O3/SiO2 coaxial nanowire heterostructures with periodical twinning structures

Al2O3/SiO2 coaxial nanowire heterostructures were synthesized on a silicon substrate by a simple thermal evaporation method. The structure and morphology of the as-synthesized nanostructure were characterized using scanning electron microscopy and transmission electron microscopy. The growth of Al2O3/SiO2 coaxial nanowire heterostructures follows a vapor-solid (VS) process. Studies indicate that typical nanostructure consists of single twinning-crystalline Al2O3 nanowires (core) with diameter of about 50 nm and amorphous SiO2 shell. Photoluminescence properties were also investigated at room temperature. The photoluminescence spectrum reveals the product has a blue emission band and two UV emission bands.