Papers by Keyword: Nanowall

Abstract: ZnO nanowalls and nanocolumns were synthesized on Si3N4 (50 nm)/Si (001) substrates at low growth temperature (350 and 400 oC) by metalorganic chemical vapor deposition (MOCVD) with no metal catalysts. ZnO nanowalls with extremely small wall thicknesses below 10 nm and nanocolumns with diameters over 100 nm were formed on the Si3N4/Si substrates relying on MOCVD-growth temperature. It was found that ZnO nanowalls have a strong c-axis preferred orientation with a hexagonal structure, while ZnO nanocolumns have a weak c-axis preferred orientation with broken stacking orders in synchrotron x-ray scattering experiments. In addition, strong free-exciton emission from the ZnO nanowalls was clearly observed in photoluminescence measurements. On the other hand, we could not observe any emission bands from the ZnO nanocolumn samples.

Abstract: Quasi-vertical ZnS nanostructures with different Ga doping level ( ZnS:Ga nanowalls ) have been synthesized in high yield from the mixed powders in the vacuum furnace at 1150 oC. ZnS:Ga nanowalls were grown vertically on the substrate with the size in the range of several microns and the thickness down to 15 nm and have very rough edges. The possible growth mechanism of nanowalls is likely governed by a vapor-solid (VS) growth mechanism. Room-temperature cathodoluminescence spectra of ZnS : Ga nanowalls show two emission peaks at approximately 443 nm and 578 nm. The emission mechanisms are discussed.