Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 41: Quantum Dots and Wires: Preparation and Characterization II
HL 41.7: Talk
Wednesday, March 24, 2010, 12:30–12:45, H13
Investigating Axial Zinc Doping Profile in Galliumarsenide Nanowires with Kelvin Force Microscopy and Scanning Microwave Microscopy — •Matthias Fenner1, Hassan Tanbakuchi1, C. Gutsche2, A. Lysov2, I. Rgolin2, W. Prost2, and F.-J. Tegude2 — 1Agilent Technologies, Campus Kronberg, 61476 Kronberg, Germany — 2Center for Nanointegration, University of Duisburg-Essen, Duisburg, Germany
Nanowires with a nominal change of the doping along the nanowire axis were grown. Fabrication of high quality doping and material transitions is well established in bulk semiconductors. This is callenging especially for III-V nanowires, where a complete model of the vapour-liquid-solid (VLS) growth mechanism is still pending. We employed two atomic force microscopy (AFM) methods for dopant profiling of GaAs nano wires: Kelvin Force Microscopy (KFM) and Scanning Microwave Microscopy (SMM). KFM indirectly measures the dopant density via the surface potential [1, 2]. SMM measures the capacitance of the tip sample junction with resolutions in the attofarad and nanometer range. By means of a local capacitance spectroscopy method (dC/dV) SMM directly maps the dopant density in semiconductors [3]. The two methods show transitions from undoped to doped regions in the nanowires as well as gradients along the axis of the wires.
[1] C. Baumgart, M. Helm, H. Schmidt, Phys. Rev. B 80, 085305 (2009). [2] S. Vinaji et al., Nanotechnology 20 (2009) [3] F. Michael Serry, Agilent Application Note 5989-8818EN, http:// cp.literature.agilent.com/litweb/pdf/5989-8818EN.pdf, 2008.