Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 20: Poster IA (Ultrafast phenomena; Optical properties; Transport; Theory)

HL 20.9: Poster

Montag, 16. März 2015, 15:00–20:00, Poster B

Lasing Dynamics in ZnO & CdS Nanowires — •Marcel Wille¹, Tom Michalsky¹, Robert Röder², Carsten Ronning², Rüdiger Schmidt-Grund¹, and Marius Grundmann¹ — ¹Institut für Experimentelle Physik II, Universität Leipzig, Linnéstraße 5, 04103 Leipzig — ²Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena

The knowledge of the turning-on characteristic as well as of the laser dynamics itself is of great importance for the application of semiconductor nanowires (NWs) as on-chip integrated nanolaser. In this work we investigated the laser dynamics of high quality, CVD grown ZnO and CdS NWs using time-resolved micro photoluminescence technique. Experiments at room temperature clearly demonstrate the formation of an electron-hole plasma in both semiconductor materials accompanied by a spectral red shift of the PL emission as well as the drop of the decay constant above laser threshold. After the high exciting laser pulse the propagating NW laser modes exhibit a red shift in time, what can be explained with the increase of the refractive index with decreasing carrier density. Remarkably, modes closer to the excitonic energy exhibit a stronger red shift than lower energetic modes. In fact the modal shift depending on the initial mode energy is significantly higher in ZnO compared to CdS NWs.