Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Quantum Dots and Wires: Preparation and Characterization I

HL 13.12: Talk

Monday, March 22, 2010, 17:00–17:15, H17

Conversion of rare earth doped ZnS to ZnO nanowires — •Sebastian Geburt, Gabriele Bulgarini, Christian Borschel, and Carsten Ronning — Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena

The ideal properties for nanoscaled photonic devices (light emission, wave guiding and light amplification) are combined in semiconductor nanowires (NWs). Doping with optical active elements offers new possibilities, but doping during nanowire growth is still an unsolved problem. Ion implantation overcomes the limitations, but the ion induced lattice damage can not completely be avoided and leads to suboptimal optical properties.

In a new approach, ZnS nanowires were implanted with rare earth elements (RE = Nd, Sm; 0.02 - 2 at%) and annealed in vacuum. Spatial resolved cathodoluminescence (CL) shows the optical activation of the RE in the ZnS matrix. Upon further annealing at higher temperatures, the ZnS nanowires were converted to ZnO by oxidation. The conversion process eliminates lattice defects and enhances the integration of the optical active dopants into their surrounding. SEM, TEM and EDX give insights to the conversion process from ZnS to ZnO. Highly enhanced luminescence from the impurities can be detected by CL. The influence of annealing conditions, dopant concentration and temperature are subject of investigation. The results are compared with RE implanted ZnO nanowires yielding into much lower intensities.