Project R-4896

Synthesis, properties and modeling of doped ZnO nanowires and nanocrystals (Research)

Zinc oxide (ZnO) has many excellent properties, including optical transparency due to a wide direct band gap of 3.37 eV. It is available as high-quality crystals with high electron mobility and thermal conductivity. Recent developments have focused on zero- and one-dimensional building blocks for new devices, which all are subject to (un)intentionel doping. ZnO based blue/ultraviolet light emitters, spintronic devices, transistors, piezoelectric nanogenerators and sensors have been realized or are being developed. Further development however requires full understanding of the influence of defects in nanosized ZnO materials, both from an experimental and a theoretical point of view, and a means to control defects from the synthesis onwards. In this project, we will investigate the influence of different defects on the doping effeciency of ZnO nanowires (NWs) and nanocrystals (NCs), paying specific attention to the reliable p-type doping. On the other hand, we will explore the influence of the nanometer size dimensions on the electronic properties. Crystaline NWs and NCs will be grown by chemical solution synthesis and vapor based approaches. The amounts of intrinsic defects, H impurities, and dopants will be controlled during ZnO growth and afterwards, by ion irradiation/implantation and by thermal annealing. The electronic (and optical) properties of the (doped) ZnO NWs and NCs, measured by electrical transport and scanning probe microscopy, Raman spectroscopy and luminescence will be interpreted based on the results of first principles calculations. BASED ON THIS COMBINED EXPERIMENTAL AND COMPUTATIONAL EFFORT AN IMPROVED UNDERSTANDING OF THE LINK BETWEEN SYNTHESIS, DEFECTS AN ELECTRONIC PROPERTIES OF NANOSTRUCTURED (DOPED) ZnO WILL BE OBTAINED.

01 January 2014 - 31 December 2017