Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 36: Quantenpunkte und -dr
ähte: Optische Eigenschaften III
HL 36.7: Vortrag
Montag, 7. März 2005, 11:30–11:45, TU P164
Stark shifts induced by internal and external electric fields in single colloidal semiconductor nanocrystals — •J. Müller1, J. M. Lupton1, A. L. Rogach1, J. Feldmann1, D. Talapin2, and H. Weller2 — 1Photonics and Optoelectronics Group, Sektion Physik, LMU Munich, 80799 Munich, Germany — 2Institute of Physical Chemistry, University of Hamburg, 20146 Hamburg, Germany
We study heterostucture nanocrystals consisting of an elongated CdS shell with a spherical CdSe core located at one end of the shell. The broken symmetry defines a spatial direction of surface charge movement towards and away from the emitting core. This leads to a change in the electric field induced Stark shift as the charges meander along the surface. We observe a universal correlation between the linewidth and the emission energy during spectral diffusion, allowing us to microscopically track the charges on a nanometer scale from 5 K up to room temperature [1]. The dependence of the fluorescence linewidth on the local electric field provides a novel probe of the nanocrystal nanoenviroment. Furthermore, application of external electric fields to single nanocrystals makes it possible to shift the emission wavelength through the Stark effect by up to 100 meV. [1] Müller et al., Phys. Rev. Lett. 93, 167402 (2004)