E. Schlenker

Determination of the specific resistance of individual freestanding ZnO nanowires with the low energy electron point source microscope

A low energy electron point source microscope is used to determine the electrical conductivity of freestanding ZnO nanowires. The nanowires were contacted with a manipulation tip and I-V curves were taken at different wire lengths. From those, the specific resistance was calculated and separated from the contact resistance. By comparing the specific resistances of ZnO nanowires with diameters between 1100 and 48nm, a large surface contribution for the thin nanowires was found. A geometric model for separation between surface and bulk contributions is given.

Properties of V-implanted ZnO nanorods

ZnO nanorods were grown on Si substrates by an aqueous chemical approach and subsequently doped by V implantation. Transmission electron microscopy and photoluminescence spectroscopy reveal a severely defective material directly after the implantation process. Subsequent annealing leads to a partial recovery of the crystal structure. The magnetic features of ZnO:V nanorods were investigated by magnetic force microscopy. Images taken of ensembles as well as of single rods clearly display contrast, which is seen as a strong indication of ferromagnetism at room temperature.