TY  - JOUR
A1  - Lee, Eun-Hye
A1  - Song, Jin-Dong
A1  - Han, Il-Ki
A1  - Chang, Soo-Kyung
A1  - Langer, Fabian
A1  - Höfling, Sven
A1  - Forchel, Alfred
A1  - Kamp, Martin
A1  - Kim, Jong-Su
T1  - Structural and optical properties of position-retrievable low-density GaAs droplet epitaxial quantum dots for application to single photon sources with plasmonic optical coupling
JF  - Nanoscale Research Letters
N2  - The position of a single GaAs quantum dot (QD), which is optically active, grown by low-density droplet epitaxy (DE) (approximately 4 QDs/μm\(^{2}\)), was directly observed on the surface of a 45-nm-thick Al\(_{0.3}\)Ga\(_{0.7}\)As capping layer. The thin thickness of AlGaAs capping layer is useful for single photon sources with plasmonic optical coupling. A micro-photoluminescence for GaAs DE QDs has shown exciton/biexciton behavior in the range of 1.654 to 1.657 eV. The direct observation of positions of low-density GaAs DE QDs would be advantageous for mass fabrication of devices that use a single QD, such as single photon sources.
KW  - quantum dot
KW  - droplet epitaxy
KW  - micro-photoluminescence
KW  - single photon
KW  - GaAs
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143692
VL  - 10
IS  - 114
ER  - 
TY  - JOUR
A1  - Wyborski, Paweł
A1  - Podemski, Paweł
A1  - Wroński, Piotr Andrzej
A1  - Jabeen, Fauzia
A1  - Höfling, Sven
A1  - Sęk, Grzegorz
T1  - Electronic and optical properties of InAs QDs grown by MBE on InGaAs metamorphic buffer
JF  - Materials
N2  - We present the optical characterization of GaAs-based InAs quantum dots (QDs) grown by molecular beam epitaxy on a digitally alloyed InGaAs metamorphic buffer layer (MBL) with gradual composition ensuring a redshift of the QD emission up to the second telecom window. Based on the photoluminescence (PL) measurements and numerical calculations, we analyzed the factors influencing the energies of optical transitions in QDs, among which the QD height seems to be dominating. In addition, polarization anisotropy of the QD emission was observed, which is a fingerprint of significant valence states mixing enhanced by the QD confinement potential asymmetry, driven by the decreased strain with increasing In content in the MBL. The barrier-related transitions were probed by photoreflectance, which combined with photoluminescence data and the PL temperature dependence, allowed for the determination of the carrier activation energies and the main channels of carrier loss, identified as the carrier escape to the MBL barrier. Eventually, the zero-dimensional character of the emission was confirmed by detecting the photoluminescence from single QDs with identified features of the confined neutral exciton and biexciton complexes via the excitation power and polarization dependences.
KW  - molecular beam epitaxy
KW  - quantum dot
KW  - metamorphic buffer layer
KW  - band structure
KW  - photoluminescence
KW  - photoreflectance
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297037
SN  - 1996-1944
VL  - 15
IS  - 3
ER  -