Tempererature-controlled growth of ZnO nanostructures: branched nanobelts and wide nanosheets

ZnO nanostructures with different morphologies have been achieved by simple thermal evaporation of mixed powders of ZnS, graphite and SnO2 at 1050 degrees C in a flowing Ar atmosphere. Branched nanobelts and wide nanosheets of ZnO were formed on Si wafers at a temperature of 700 and 500 degrees C, respectively. As for the branched nanobelts, there exist nanotwins along the axial direction of the stem belts, and a definite included angle about 70 degrees between the stem and the branch. In contrast, the wide nanosheets have a rectangle-like cross-section with typical widths of 200 nm to several micrometres and lengths of up to tens of micrometres. Photoluminescence measurements reveal that the branched nanobelts and wide nanosheets have visible green emission bands at about 530 and 5 10 nm, respectively. The branched ZnO nanobelts have potential for building optoelectronic nanodevices with special configurations, and the ZnO nanosheets might be used in nanoscale sensors.