Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 38: ZnO and Related Semiconductors

HL 38.3: Talk

Wednesday, March 24, 2010, 10:00–10:15, H17

Gain dynamics of single ZnO nanowires — •Jan-Peter Richters, Jürgen Gutowski, and Tobias Voss — Institute of Solid State Physics, University of Bremen, P.O. Box 330440, D-28334 Bremen

Nanostructures of large band-gap semiconductors like ZnO are of great interest as light emitting and lasing media in the blue-UV spectral range. In order to use ZnO nanowires as lasing devices it is important to understand the spectral and temporal characteristics of their material and modal gain. Theoretical calculations predict a very high modal gain close to the material gain for semiconductor nanowires which is due to the very high confinement of the light for such nanostructures.

We investigate the gain of single ZnO nanowires under excitation with fs-laser pulses from a frequency tripled regenerative amplifier (800 nm, pulse duration less than 100fs, repetition rate 1kHz, pulse power 3 mJ) using the variable-stripe-length method allowing for the investigation of the profile of their modal gain. The measurements are carried out at room temperature on a glas substrate. We ammount the modal gain to 6000 - 8000 cm⁻¹ for nanowires with diameters larger than 200 nm. These results are in good agreement with theoretical predictions from the literature where a values of up to 2500 cm⁻¹ for GaN nanowires with a diameter of 105nm has been calculated.