Probing ultrafast carrier tunneling dynamics in individual quantum dots and molecules

被引:16
作者
Mueller, Kai [1 ,2 ]
Bechtold, Alexander [1 ,2 ]
Ruppert, Claudia [3 ]
Kaldewey, Timo [1 ,2 ]
Zecherle, Markus [1 ,2 ]
Wildmann, Johannes S. [1 ,2 ]
Bichler, Max [1 ,2 ]
Krenner, Hubert J. [4 ,5 ]
Villas-Boas, Jose M. [6 ]
Abstreiter, Gerhard [1 ,2 ]
Betz, Markus [3 ]
Finley, Jonathan J. [1 ,2 ]
机构
[1] Tech Univ Munich, Walter Schottky Inst, D-85748 Garching, Germany
[2] Tech Univ Munich, Dept Phys, D-85748 Garching, Germany
[3] TU Dortmund, D-44221 Dortmund, Germany
[4] Univ Augsburg, Lehrstuhl Expt Phys 1, D-86159 Augsburg, Germany
[5] Univ Augsburg, Augsburg Ctr Innovat Technol ACIT, D-86159 Augsburg, Germany
[6] Univ Fed Uberlandia, Inst Fis, BR-38400902 Uberlandia, MG, Brazil
关键词
Quantum dot molecules; ultrafast pump-probe spectroscopy; inelastic tunneling; tunnel coupling;
D O I
10.1002/andp.201200195
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Ultrafast pump-probe spectroscopy is employed to directly monitor the tunneling of charge carriers from single and vertically coupled quantum dots and probe intra-molecular dynamics. Immediately after resonant optical excitation, several peaks are observed in the pump-probe spectrum arising from Coulomb interactions between the photogenerated charge carriers. The influence of few-Fermion interactions in the photoexcited system and the temporal evolution of the optical response is directly probed in the time domain. In addition, the tunneling times for electrons and holes from the QD nanostructure are independently determined. In polarization resolved measurements, near perfect Pauli-spin blockade is observed in the spin-selective absorption spectrum as well as stimulated emission. While electron and hole tunneling from single quantum dots is shown to be well explained by the WKB formalism, for coupled quantum dots pronounced resonances in the electron tunneling rate are observed arising from elastic and inelastic electron tunneling between the different dots.
引用
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页码:49 / 58
页数:10
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