Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 12: Quantum Dots and Wires: Arsenides
HL 12.2: Talk
Monday, March 14, 2011, 12:15–12:30, POT 151
Spatially resolved photocurrent spectroscopy on a single pn-doped GaAs nanowire — •Daniel Sager1, Christoph Gutsche2, Andrey Lysov2, Matthias Offer3, Ingo Regolin2, Werner Prost2, Franz-Josef Tegude2, Axel Lorke3, and Gerd Bacher1 — 1Werkstoffe der Elektrotechnik & CeNIDE, Universität Duisburg-Essen, Bismarckstr. 81, 47057 Duisburg, Germany — 2Halbleitertechnologie & CeNIDE, Universität Duisburg-Essen, Lotharstr. 55, 47048 Duisburg, Germany — 3Experimentalphysik & CeNIDE, Universität Duisburg-Essen, Lotharstr. 55, 47048 Duisburg, Germany
Due to their geometry, nanowires based on direct bandgap semiconductors are seen as ideal candidates for photovoltaic applications. Therefore, a detailed knowledge of the light to charge conversion process is essential for the future device design of solar cells. This can be accessed by spatially and temporally resolved photocurrent spectroscopy.
Single GaAs nanowires grown by metal-organic vapour phase epitaxy have been doped with Zn and Sn for p- and n-type doping, respectively, to create a doping transition in axial direction [1]. With spatially resolved photocurrent spectroscopy electron-hole pairs are photo-generated and the resulting current is measured as a function of the laser spot position. A photocurrent, which is proportional to the light illumination is found. We demonstrate maximum photocurrent generation directly at the pn-junction, which is strongly decreasing if the laser spot is placed outside the junction.
[1] I.Regolin, et al., J. Cryst. Growth (2010), doi:10.1016/j.jcrysgro.2010.08.028