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HL: Fachverband Halbleiterphysik

HL 49: ZnO: Optical properties

HL 49.1: Vortrag

Donnerstag, 28. Februar 2008, 10:45–11:00, ER 164

Lasing modes in ZnO microwires — •Christian Czekalla, Jörg Lenzner, Rüdiger Schmidt-Grund, Bingqjang Cao, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstr. 5, 04103, Leipzig, Germany

We report lasing from single hexagonally shaped ZnO microwires detected using spatially resolved photoluminescence spectroscopy (PL) under high excitation conditions. The structures were synthesized by a carbothermal evaporation process at ambient pressure and show a efficient excitonic radiative recombination at low excitation intensities. The wires were either dispersed on silicon or sapphire substrates or on carbon gluepads. Under high excitation conditions at low temperature, additional peaks due to inelastic exciton collisions and the formation of an electron hole plasma can be seen. Furthermore, sharp peaks are observed in the spectra growing superlinearly with the excitation intensity, indicating stimulated emission and lasing from Fabry-Perot-modes between the side facets of the microwires with a resonator length between 3 µm and 20 µm. The peaks exhibit a FWHM of only 2 meV and a lasing threshold intensity of about 150 kW/cm². Spectra as a function of temperature, wire diameter and polarization will be presented.