Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: ZnO: Preparation and characterization I
HL 9.5: Vortrag
Montag, 25. Februar 2008, 16:00–16:15, EW 201
Structural and electronic properties of ZnO nanowires and nanotubes — •Andreia Luisa da Rosa1, Hu Xu2, Wei Fan2, Fei Zhan2, Xiaohong Zhang2, Ruiqin Zhang3, and Thomas Frauenheim1 — 1BCCMS, Universität Bremen, Am Fallturm 1, 28359, Bremen, Germany — 2Nano-organic Photoelectronic Laboratory, Technical Institute of Physics and Chemistry, Beijing 100101, China — 3COSDAF, Department of Physics and Materials Science, City University of Hong Kong SAR, China
ZnO is a well known semiconductor with potential applications in electronics and optoelectronics. ZnO has a direct wide band gap of 3.3 eV and a large exciton binding energy making it promising for high-efficiency blue and ultra-violet devices. Recently, the successful growth of highly ordered nanowires has expanded the list of potential applications. In this work we employ density functional theory to investigate ZnO nanowires and nanotubes. We find that relaxations on the facets are very similar to the ones in non-polar ZnO surfaces. While bare and completely passivated wires are semiconducting, wires with intermediate hydrogen passivation exhibit metallic behavior. We therefore suggest that hydrogenation leads to drastic changes in the ZnO nanowire electrical properties. We have also investigated ZnO nanotubes with round and hexagonal shapes. The calculated strain energy of round ZnO nanotubes follows a classical strain law. All the ZnO nanotubes were found to be direct band gap semiconductors with the band gap decreasing as their diameter increases.