Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 19: Quantum dots and wires: Optical properties II
HL 19.4: Vortrag
Dienstag, 28. März 2006, 18:00–18:15, HSZ 01
Storage of excitons in elongated semiconductor nanocrystals — •Robert M. Kraus1, Pavlos G. Lagoudakis1, Andrey L. Rogach1, John M. Lupton1, Jochen Feldmann1, Dmitry Talapin2, and Horst Weller2 — 1Photonics and Optoelectronics Group, Physics Department and CeNS, Ludwig-Maximilians-Universität München, Germany — 2Institute of Physical Chemistry, University of Hamburg, Germany
Spherical CdSe nanocrystals capped by a CdS rod-like shell, referred to as nanorods, exhibit interesting spectral dynamics on the single particle level.[1,2] However, for the purpose of applications, the ensemble properties of nanorods are most interesting. We are especially interested in the behaviour of an ensemble of nanorods under the influence of an electric field, as this bears great relevance for future devices. We show here that by applying an electric field to an ensemble of nanorods in a vertical sample geometry a linear quantum-confined Stark shift of the order of 60 meV can be observed in the emission energy. During the application of the electric field the excitons are effectively hindered from radiative recombination and can be stored coulombically for up to 100 µs. Furthermore, modulation of the electric field leads to a modulation in both the wavelength and the spectral width of the nanoparticle emission.
[1] J. Müller et al., Phys. Rev. Lett. 93, 167402 (2004)
[2] J. Müller et al., Nanoletters 5, 2044 (2005)