Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 23: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy

O 23.13: Poster

Montag, 7. März 2016, 18:15–20:30, Poster E

Investigation of carrier concentrations in doped InAs using SNOM measurements to quantify and improve signal modelling — •Maximilian Sauer, Lena Jung, and Thomas Taubner — I. Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

The scattering-type scanning near-field optical microscope (s-SNOM) consists of an AFM where the tip is illuminated by an infrared laser to create near-fields at the tips apex, which has a radius of typically 25nm. With SNOM it is possible to investigate the optical and electrical properties, including the dielectric function, of doped semiconductors with a spatial resolution that can be below the diffraction limit because it is given by the tip’s radius. Hereby, the so called Finite Dipole Model (FDM) in combination with the Drude model is used to calculate SNOM signals to compare with actual measurement data. Within these models, the carrier concentration of a material can be extracted from the signals amplitude and phase at different wavelengths.

Doped bulk InAs samples with known electrical properties like carrier concentration due to investigation via other measurement techniques like Hall measurements are investigated with SNOM. The model’s predictions based on our SNOM measurements can be compared with the known properties. The results of this comparison are used to examine if the models need to be improved in order to correctly describe the data. The next step is the expansion of the investigation to nanostructures, for example determining and imaging the electrial properties of nanowires, to make use of SNOM’s high spatial resolution.