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HL: Fachverband Halbleiterphysik
HL 30: Nano Wires: Growth and Characterization
HL 30.3: Talk
Tuesday, March 15, 2011, 10:45–11:00, FOE Anorg
Doping dependence of the electrochemical properties of GaN:Si nanowires. — •Jens Wallys1, Florian Furtmayr1,2, Rudolph Matz1, Marcus Rohnke3, and Martin Eickhoff1 — 1I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen — 2Walter Schottky Institut, Technische Universitaet Muenchen — 3Physikalisch-Chemisches Institut, Justus-Liebig-Universitaet Giessen
Recently, the interest in self assembled nanowires (NW) increased due to their low density of structural defects, the possibility of doping and embedding III-N heterostructures, which allow the realization of novel nanoscale optoelectronic devices, such as light emitters and chemical sensors. For these applications understanding and control of dopant incorporation is an important issue. While investigations based on electron microscopy or optical methods provide valuable information, the determination of the doping concentration in NWs is still problematic since many conventional methods (e.g. Hall measurements) are not applicable.
In this study we investigated various Si-doped GaN NWs grown by plasma assisted molecular beam epitaxy. In order to determine the Si concentration we performed electrical impedance spectroscopy measurements of NW-ensembles. This allows us to extract the surface capacitance and surface resistance via numerical fitting of electrical equivalent circuits to the experimental spectra. The obtained results were compared to time of flight - secondary ion mass spectroscopy measurements as an alternative approach. In addition, the effect of NW-ageing is addressed.