2024-03-29T15:06:53Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/319762022-07-16T00:58:54Zcom_10261_36com_10261_4col_10261_289
Enhancement of the photoluminescence intensity of a single InAs/GaAs quantum dot by separate generation of electrons and holes
Donchev, V.
Moskalenko, E. S.
Karlsson, K. F.
Holtz, P. O.
Monemar, B.
Schoenfeld, W. V.
García Martínez, Jorge Manuel
Petroff, Pierre M.
7 páginas, 5 figuras.-- PACS numbers: 78.67.Hc, 71.55.Eq, 73.50.Gr
It is demonstrated that the microphotoluminescence (μPL) spectrum of a single InAs/GaAs self-assembled quantum dot (QD) undergoes considerable changes when the primary laser excitation is complemented with an additional infrared laser. The primary laser, tuned slightly below the GaAs band gap, provides electron-hole pairs in the wetting layer (WL), as well as excess free electrons from ionized shallow acceptors in the GaAs barriers. An additional IR laser with a fixed energy well below the QD ground state transition generates excess free holes from deep levels in GaAs. The excess electron and hole will experience diffusion separately, due to the time separation between the two events of their generation, to eventually become captured into the QD. Although the generation rates of excess carries are much lower than that of the electron-hole pair generation in the WL, they considerably influence the QD emission at low temperatures. The integrated PL intensity increases by several times as compared to single-laser excitation, and the QD exciton spectrum is redistributed in favor of a more neutral charge configuration. The dependence of the observed phenomenon on the powers of the two lasers and the temperature has been studied and is consistent with the model proposed. The concept of dual excitation could be successfully applied to different low-dimensional semiconductor structures in order to manipulate their charge state and emission intensity.
This work was supported by grants from the Swedish
Foundation for Strategic Research (SSR) and Swedish
Research Council (VR). Financial support from the
Wenner-Gren Foundation and the program “Low-
Dimensional Quantum Structures” of the Russian
Academy of Sciences is acknowledged by E.S.M. V.D.
is thankful for financial support from the Swedish
Foundation for International Cooperation in Research
and Higher Education (STINT) and from the Bulgarian
National Science Fund.
Peer reviewed
2011-02-03T14:01:25Z
2011-02-03T14:01:25Z
2006
artículo
http://purl.org/coar/resource_type/c_6501
Physics of the Solid State 48(10): 1993-1999 (2006)
1063-7834
http://hdl.handle.net/10261/31976
10.1134/S1063783406100295
en
http://dx.doi.org/10.1134/S1063783406100295
open
Springer