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HL: Fachverband Halbleiterphysik

HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices

HL 25.24: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Electrochemical characterization of Si- and Mg- doped GaN nanowire electrodes — •Jens Wallys¹, Florian Furtmayr^1,2, Jörg Teubert¹, Wladimir Schäfer¹, Jörg Schörmann¹, and Martin Eickhoff¹ — ¹I. Physikalisches Institut, Justus-Liebig-Universität Gießen — ²Walter Schottky Institut, Technische Universität München

Recent progress in the field of GaN nanowire (NW) growth, in particular the possibility to realize both p- and n-type doping, suggest their use as novel electrodes for chemical and biological sensors or in the field of photo catalysis. However, the knowledge about their electrochemical properties and the influence of doping is still very limited.

We investigated ensembles of undoped, Si-doped and Mg-doped GaN NWs with different doping concentrations and average diameters grown on Si (111) substrates by plasma assisted molecular beam epitaxy. The samples were analyzed using bias dependent electrochemical impedance spectroscopy measurements under physiological electrolyte conditions. By fitting the results to an equivalent circuit model the electronic properties of GaN NW ensembles could be extracted. According to these results a classification of the NWs into conducting and depleted ones is suggested and verified by cyclic voltamogramms in the presence of a redox couple and correlated to scanning electron microscope images.