Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 26: II-VI semiconductors II
HL 26.14: Talk
Tuesday, March 28, 2006, 18:30–18:45, POT 51
Optical characterisation of ZnO nanostructures grown by various methods — •Chegnui Bekeny1, Houcem Gafsi1, Tobias Voss1, Bianca Postels2, Marc Kreye2, Sandra Börner3, and Wolfgang Schade3 — 1Institute of Solid State Physics, University of Bremen, P.O Box 330440, D-28334 Bremen — 2IHT, TU Braunschweig, P.O Box 3329, D-38023 Braunschweig — 3IPPT, TU Clausthal, Leibnizstraße 4, D-38678, Clausthal-Zellerfeld
ZnO, a semiconductor with a band gap of 3.37 eV, is currently in the focus of research due to its relatively large exciton binding energy of 60 meV and its ability to emit light in the uv spectral region. In order to integrate ZnO nanostructures into optoelectronic devices, it is imperative to thoroughly understand their optical properties. We present systematic photoluminescence studies of ZnO nanorods fabricated by aqueous chemical growth (ACG). These nanorods show significant near band-edge excitonic luminescence accompanied by very little green and orange defect luminescence. In combination with distinct phonon replica of the excitonic lines observed this indicates a good optical quality of the ACG nanorods. The optical properties of nanorods grown on different substrates (Si and plastic foil) will be compared with ZnO nanostructures grown by other epitaxial methods. Additional investigations concerning possible laser action in ZnO nanowires were performed using vapour-liquid-solid grown nanowires. At high excitation densities (>0.5 MW/cm*) single nanowires (dispersed on a sapphire substrate) showed a narrow emission line at ~3.2 eV (line width 0.5 meV) even at room temperature.