Abstract-Inter-sublevel dynamics in single InAs/GaAs quantum dots induced by strong terahertz excitation

D. Stephan1,2,a), J. Bhattacharyya1,b), Y. H. Huo3,4, O. G. Schmidt3, A. Rastelli3,4, M. Helm1,2 and H. Schneider1


1 Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany
2 Technische Universität Dresden, 01062 Dresden, Germany
3 Institute for Integrative Nanosciences, IFW Dresden, 01069 Dresden, Germany
4 Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
a) Electronic mail: d.stephan@hzdr.de
b) Present address: Indian Institute of Technology Madras, IIT P.O., Chennai 600 036, India.
Appl. Phys. Lett. 108, 082107 (2016); http://dx.doi.org/10.1063/1.4942893

We combine micro-photoluminescence(PL) with terahertz excitation to investigate the response of singleself-assembled InAs/GaAs quantum dots to intense terahertz pulses tuned to the s-to-p transition. Spectra and transients of single photoluminescence lines reveal the dynamics of electrons upon excitation and subsequent relaxation back into the initial state. Under certain circumstances, the terahertz pulse can release trapped charge carriers, which relax into the quantum dot. Furthermore, we demonstrate near-total depletion of the positive trionPL by an intense terahertz pulse.