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HL: Fachverband Halbleiterphysik

HL 25: Quantum dots and wires: Optical properties II

HL 25.4: Vortrag

Dienstag, 27. März 2007, 14:45–15:00, H17

Low treshold stimulated emission in Yb-doped ZnO-nanowires — •Sebastian Geburt¹, Daniel Stichtenoth¹, Sven Müller¹, Wilma Dewald¹, Carsten Ronning¹, Juan Wang², and Quan Li² — ¹II. Institute of physics, University of Göttingen, Freidrich-Hund-Platz 1, 37077 Göttingen, Germany — ²Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong

Rare earth elements embedded in suitable matrices show optical active intra-4f-transitions with long life-times. Such states are necessary e.g. for the realization of Nd:YAG-lasers. Because of their geometry, semiconductor nanowires could act as cavity; therefore, rare earth doped semiconductor nanowires may be suitable for nanosized lasers.

ZnO nanowires were grown by the VLS mechanism using the vapour transport technique, dispersed in 2-propanol and spincoated on clean Si-substrates. Yb was implanted with a box like profile and different fluences. In order to remove the implantation damage, the nanowires were annealed at 700°C for 30min in oxygen atmosphere.

The morphology was examined by SEM and HR-TEM. The remaining implantation damage increased with increasing fluences, thin nanowires showed a stronger morphology change and roughening of the surface occured. EDX and EELS measurements showed effective incorporation of the RE elements with the desired concentrations. The optical properties were investigated using PL. The measurements showed a sharp intense peak at 1.26eV associated with intra-4f-transitions of Yb with a low quenching up to room temperature. The power dependend measurements indicate stimulated emission.