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HL: Fachverband Halbleiterphysik

HL 37: ZnO: devices

HL 37.4: Vortrag

Mittwoch, 25. März 2009, 17:15–17:30, POT 51

Lasing emission in ZnO nanorods — •Victor Zalamai¹, Johannes Fallert¹, Janos Sartor¹, Daniel Schneider¹, Heinz Kalt¹, Claus Klingshirn¹, Veaceslav Ursaki², and Ion Tiginyanu² — ¹Institut für Angewandte Physik, Universität Karlsruhe (TH), Germany — ²Technical University of Moldova, Moldova

In this work we investigate lasing effects in zinc oxide nanorods. Vertically aligned hexagonal ZnO nanorods have been prepared by low pressure chemical vapour deposition (CVD). The photoluminescence (PL) spectroscopy demonstrates the high crystal quality of the produced nanorods which is comparable with the quality of bulk ZnO single crystals. The transition from spontaneous to stimulated emission is observed in arrays of hexagonal nanorods with an almost uniform diameter of 200 nm and length of 1.5 µm under excitation by 5 ns laser pulses above a certain threshold of excitation power density which depends from nanorod sizes. Multiple sharp peaks representing different lasing modes emerge in the emission spectrum above the lasing threshold. The lasing modes are better resolved when the emission from a single nanorod is analyzed. A broad emission band is characteristic for randomly oriented ZnO nanostructures with a variety of geometrical parameters. This band represents a superposition of lasing modes coming from ZnO nanorods with different diameters and lengths.