Publications (2)16.78 Total impact
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Article: Intersublevel spectroscopy on single InAs-quantum dots by terahertz near-field microscopy.
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ABSTRACT: Using scattering-type near-field infrared microscopy in combination with a free-electron laser, intersublevel transitions in buried single InAs quantum dots are investigated. The experiments are performed at room temperature on doped self-assembled quantum dots capped with a 70 nm GaAs layer. Clear near-field contrast of single dots is observed when the photon energy of the incident beam matches intersublevel transition energies, namely the p-d and s-d transition of conduction band electrons confined in the dots. The observed room-temperature line width of 5-8 meV of these resonances in the mid-infrared range is significantly below the inhomogeneously broadened spectral lines of quantum dot ensembles. The experiment highlights the strength of near-field microspectroscopy by demonstrating signals from bound-to-bound transitions of single electrons in a probe volume of the order of (100 nm)(3).Nano Letters 07/2012; 12(8):4336-40. · 13.20 Impact Factor -
Article: Quantitative determination of the charge carrier concentration of ion implanted silicon by IR-near-field spectroscopy.
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ABSTRACT: We use a combination of a scattering-type near-field infrared microscope with a free-electron laser as an intense, tunable radiation source to spatially and spectrally resolve buried doped layers in silicon. To this end, boron implanted stripes in silicon are raster scanned at different wavelengths in the range from 10 to 14 µm. An analysis based on a simple Drude model for the dielectric function of the sample yields quantitatively correct values for the concentration of the activated carriers. In a control experiment at the fixed wavelength of 10.6 µm, interferometric near-field signals are recorded. The phase information gained in this experiment is fully consistent with the carrier concentration obtained in the spectrally resolved experiments.Optics Express 12/2010; 18(25):26206-13. · 3.59 Impact Factor
Top co-authors
Top Journals
- Optics Express (1)
- Nano Letters (1)
Institutions
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2010–2012
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Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Ion Beam Physics and Materials Research
Dresden, Saxony, Germany
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