TREATMENT OF ZnO NANOWIRES on Si(111)

ZnO NWs attracted renewed attention in recent years due to their peculiar optical properties [1-2]. This material system is a promising candidate for short wavelength optoelectronic devices. The attention on ZnO has considerably enhanced since the first report on p-doped ZnO light emitting diodes was published [3]. Many room-temperature applications have already been shown, such as single-NW field-effect transistors, laser diodes, solar cells, and sensors [4]. Despite the recent progress in fabrication of NW devices, the low-temperature properties of semiconductor NWs and their potential for novel quantum devices are still widely unexplored. Self-organized ZnO NWs have substantial advantages compared to other material systems (no surface oxidation, high exciton binding energy, ferromagnetic properties when doped with transition elements). A key property of these material systems is the unique versatility in terms of geometrical dimensions and composition. However, for any application a detailed knowledge about the optical properties, their microscopic origin, surface morphology and cross section, which is influenced by e.g. growth methods or the geometry of the nanostructures, are of fundamental importance