Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)
File(s)
Author(s)
Type
Journal Article
Abstract
The design of some optical devices, such as semiconductor optical amplifiers for telecommunication
applications, requires polarization-insensitive optical emission at long wavelengths (1300–1550 nm).
Self-assembled InAs/GaAs quantum dots (QDs) typically exhibit ground state optical emissions at
wavelengths shorter than 1300 nm with highly polarization-sensitive characteristics, although this can
be modified by the use of low growth rates, the incorporation of strain-reducing capping layers, or the
growth of closely-stacked QD layers. Exploiting the strain interactions between closely stacked QD
layers also affords greater freedom in the choice of growth conditions for the upper layers, so that both
a significant extension in their emission wavelength and an improved polarization response can be
achieved due to modification of the QD size, strain, and composition. In this paper, we investigate the
polarization behavior of single and stacked QD layers using room temperature sub-lasing-threshold
electroluminescence and photovoltage measurements, as well as atomistic modeling with the NEMO
3-D simulator. A reduction is observed in the ratio of the transverse electric (TE) to transverse
magnetic (TM) optical mode response for a GaAs-capped QD stack as compared to a single QD layer,
but when the second layer of the two-layer stack is InGaAs-capped, an increase in the TE/TM ratio is
observed, in contrast to recent reports for single QD layers.
applications, requires polarization-insensitive optical emission at long wavelengths (1300–1550 nm).
Self-assembled InAs/GaAs quantum dots (QDs) typically exhibit ground state optical emissions at
wavelengths shorter than 1300 nm with highly polarization-sensitive characteristics, although this can
be modified by the use of low growth rates, the incorporation of strain-reducing capping layers, or the
growth of closely-stacked QD layers. Exploiting the strain interactions between closely stacked QD
layers also affords greater freedom in the choice of growth conditions for the upper layers, so that both
a significant extension in their emission wavelength and an improved polarization response can be
achieved due to modification of the QD size, strain, and composition. In this paper, we investigate the
polarization behavior of single and stacked QD layers using room temperature sub-lasing-threshold
electroluminescence and photovoltage measurements, as well as atomistic modeling with the NEMO
3-D simulator. A reduction is observed in the ratio of the transverse electric (TE) to transverse
magnetic (TM) optical mode response for a GaAs-capped QD stack as compared to a single QD layer,
but when the second layer of the two-layer stack is InGaAs-capped, an increase in the TE/TM ratio is
observed, in contrast to recent reports for single QD layers.
Date Issued
2011-05-15
Date Acceptance
2011-04-05
Citation
Journal of Applied Physics, 2011, 109 (10)
ISSN
1089-7550
Publisher
American Institute of Physics (AIP)
Journal / Book Title
Journal of Applied Physics
Volume
109
Issue
10
Copyright Statement
© 2011 American Institute of Physics.
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Commission of the European Communities
Engineering & Physical Science Research Council (E
Engineering & Physical Science Research Council (EPSRC)
Ingenia Holdings Limited
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Grant Number
GR/S05762/01
HPRN-CT-2002-00315
GR/R55078/01
EP/C511972/1
DVP/EJV
EP/F031688/1
EP/H000488/1
Subjects
Science & Technology
Physical Sciences
Physics, Applied
Physics
PHYSICS, APPLIED
ATOMISTIC SIMULATION
NEMO 3-D
GAAS
ANISOTROPY
LASERS
Publication Status
Published
Article Number
104510