Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 37: Quantum Dots and Wires: Optical Properties I (mainly InGaAs Dots)
HL 37.9: Vortrag
Dienstag, 27. März 2012, 12:45–13:00, ER 164
Scanning near-field infrared micro-spectroscopy on buried InAs quantum dots — •Markus Fehrenbacher1, Rainer Jacob1, Stephan Winnerl1, Harald Schneider1, Manfred Helm1, Marc Tobias Wenzel2, Anja Krysztofinski2, Hans-Georg von Ribbeck2, and Lukas M. Eng2 — 1Institut für Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden- Rossendorf, Germany — 2Institut für Angewandte Photophysik, TU Dresden, Germany
Providing an optical resolution on the nanometer length scale, scanning near-field optical microscopy (SNOM) turned out to be a capable technique to investigate the optical properties of perovskites [1], buried semiconductors [2] and single quantum dots [3]. Thereby, the line-width of the observed resonances (5 - 8 meV) is significantly smaller than the inhomogeneously broadened line-width of other spectroscopic measurements. Using a scattering-type-SNOM (s-SNOM) combined with a tunable free-electron laser (FEL) light source we investigated the electronic structure of single InAs quantum dots, capped under a 70 nm thick GaAs layer [3]. Spectroscopic near-field scans clearly identified two inter-sublevel transitions within the quantum dots at 85 meV and 120 meV, contrasting from the surrounding medium. Moreover, spatially scanning the s-SNOM tip at fixed excitation energies allowed mapping the 3D distribution of such buried quantum dots.
[1] S. Kehr et al. Nature Comm. 2, 249 (2011) [2] R. Jacob et al., Optics Ex. 18, 26206 (2010) [3] R. Jacob, PhD thesis, TU Dresden (2011)