Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 30: Nano Wires: Growth and Characterization

HL 30.3: Vortrag

Dienstag, 15. März 2011, 10:45–11:00, FOE Anorg

Doping dependence of the electrochemical properties of GaN:Si nanowires. — •Jens Wallys¹, Florian Furtmayr^1,2, 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.