Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Plasmonics and Nanooptics III: Infrared Microscopy
O 42.1: Vortrag
Dienstag, 8. März 2016, 14:00–14:15, H4
Determination of local variations in charge carrier concentrations of doped nanowires using infrared near-field microscopy — •Lena Jung1, Robert Ukropec1,2, Fabian Haas2, Hilde Hardtdegen2, Thomas Schäpers2, and Thomas Taubner1 — 1I. Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany — 2Peter Grünberg Institut 9, Forschungszentrum Jülich, 52425 Jülich, Germany
In scattering-type scanning near-field optical microscopy (s-SNOM), optical near-fields are generated at the apex of a sharp illuminated tip. The near-fields interact with the part of the sample in close proximity to the tip, therefore the back-scattered light contains information about the optical properties of the sample with a resolution only limited by the sharpness of the tip. We use this high resolution for the investigation of local variations in the charge carrier density of doped semiconductor nanowires (NW). Since the SNOM signals are related to the dielectric function of the sample material, which in turn can be connected to charge carrier density and mobility for doped semiconductors by applying the Drude model, it is possible to determine these important quantities from the spectroscopic SNOM signals. Measurements on partly doped Si-NW will be presented as well as on contacted InAs-NW. With a sample holder that allows contacting the sample, which was specifically designed for this sample system, we were able to perform SNOM measurements of these NW by at the same time applying a source-drain voltage and a backgate to the nanowires. This allows for the investigation of the direct influence of gating on the NW.