Carrier relaxation and electronic structure in InAs self-assembled quantum dots

authored by: Klaus H. Schmidt, G. Medeiros-Ribeiro, Michael Oestreich, P. Petroff, G. Döhler
Abstract: We studied the electronic structure and relaxation processes in InAs quantum dots embedded in GaAs. Using capacitance measurements along with photoluminescence spectroscopy, we estimate the energy splitting between the ground and first excited quantum-dot state in the conduction and valence band, respectively. There are five quantum-dot transitions observable in our photoluminescence (PL) spectra, which we attribute to allowed transitions between electron and hole states of the same quantum number. Phonon-related relaxation processes were studied combining PL, resonant PL (RPL), and photoluminescence excitation (PLE) experiments. In the RPL as well as in the PLE spectra, we observed enhanced signals at twice the phonon energies available in the system. Therefore, a maximum in the intensity of the PLE and RPL signal does not necessarily occur when most of the dots are pumped resonantly into an excited state. The main criterion, however, seems to be that the energy distance between the pumped levels and the levels below matches a multiple of the available phonon energies. Changing the pump power in our resonant PL experiments corroborates that at least in the small carrier density regime phonon-related processes are important for the carrier relaxation in InAs quantum dots embedded in GaAs bulk material.
External Organisation(s): University of California at Santa Barbara
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU Erlangen-Nürnberg)
Type: Article
Journal: Physical Review B - Condensed Matter and Materials Physics
Volume: 54
Pages: 11346-11353
No. of pages: 8
ISSN: 1098-0121
Publication date: 15.10.1996
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): https://doi.org/10.1103/PhysRevB.54.11346 (Access: Unknown)

BibTeX

@article{f8e035a2c10c43d98ec69833fd4d0aef,
title = "Carrier relaxation and electronic structure in InAs self-assembled quantum dots",
abstract = "We studied the electronic structure and relaxation processes in InAs quantum dots embedded in GaAs. Using capacitance measurements along with photoluminescence spectroscopy, we estimate the energy splitting between the ground and first excited quantum-dot state in the conduction and valence band, respectively. There are five quantum-dot transitions observable in our photoluminescence (PL) spectra, which we attribute to allowed transitions between electron and hole states of the same quantum number. Phonon-related relaxation processes were studied combining PL, resonant PL (RPL), and photoluminescence excitation (PLE) experiments. In the RPL as well as in the PLE spectra, we observed enhanced signals at twice the phonon energies available in the system. Therefore, a maximum in the intensity of the PLE and RPL signal does not necessarily occur when most of the dots are pumped resonantly into an excited state. The main criterion, however, seems to be that the energy distance between the pumped levels and the levels below matches a multiple of the available phonon energies. Changing the pump power in our resonant PL experiments corroborates that at least in the small carrier density regime phonon-related processes are important for the carrier relaxation in InAs quantum dots embedded in GaAs bulk material.",
author = "Schmidt, {Klaus H.} and G. Medeiros-Ribeiro and Michael Oestreich and P. Petroff and G. D{\"o}hler",
year = "1996",
month = oct,
day = "15",
doi = "10.1103/PhysRevB.54.11346",
language = "English",
volume = "54",
pages = "11346--11353",
journal = "Physical Review B - Condensed Matter and Materials Physics",
issn = "1098-0121",
publisher = "American Institute of Physics",
number = "16",
}