Xiaohong An

Electrochemical synthesis of metal and semimetal nanotube–nanowire heterojunctions and their electronic transport properties

Metal and semimetal nanotube-nanowire heterojunction arrays have been achieved by sequential electrochemical-deposition inside the nanochannels of anodic aluminium oxide template with a layer of Au thin enough to leave the pores open.

Temperature-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 ◦ Ci na flowing Ar atmosphere. Branched nanobelts and wide nanosheets of ZnO were formed on Si wafers at a temperature of 700 and 500 ◦ C, respectively. As fo rt he branched nanobelts, there exist nanotwins along the axial direction of the stem belts, and a definite included angle about 70 ◦ 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 510 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.

Synthesis of SnO2 nanostructures by carbothermal reduction of SnO2 powder

The mass preparation of SnO2 nanobelts and nanowires has been achieved by carrying out the reaction of SnO2 powder and graphite at 1150°C. A metallic catalyst and vacuum conditions are not necessary. The temperature of the substrates and the concentration of oxide vapour were the critical experimental parameters for the formation of different morphologies of SnO2 nanostructures. The as-synthesized SnO2 nanobelts formed in region II are single crystalline with a [101] growth axis, with widths ranging from 50 to 500 nm, width-to-thickness ratios of 5–10, and lengths up to a few millimetres.