2 research outputs found
Epitaxial growth and characterization of multi-layer site-controlled InGaAs quantum dots based on the buried stressor method
We report on the epitaxial growth, theoretical modeling, and structural as
well as optical investigation of multi-layer, site-controlled quantum dots
fabricated using the buried stressor method. This advanced growth technique
utilizes the strain from a partially oxidized AlAs layer to induce
site-selective nucleation of InGaAs quantum dots. By implementing
strain-induced spectral nano-engineering, we achieve separation in emission
energy by about 150 meV of positioned and non-positioned quantum dots and a
local increase of the emitter density in a single layer. Furthermore, we
achieve a threefold increase of the optical intensity and reduce the
inhomogeneous broadening of the ensemble emission by 20% via stacking three
layers of site-controlled emitters, which is particularly valuable for using
the SCQDs in microlaser applications. Moreover, we obtain direct control over
emission properties by adjusting the growth and fabrication parameters. Our
optimization of site-controlled growth of quantum dots enables the development
of photonic devices with enhanced light-matter interaction and microlasers with
increased confinement factor and spontaneous emission coupling efficiency
GaAs quantum dots under quasi-uniaxial stress: experiment and theory
The optical properties of excitons confined in initially-unstrained
GaAs/AlGaAs quantum dots are studied as a function of a variable quasi-uniaxial
stress. To allow the validation of state-of-the-art computational tools for
describing the optical properties of nanostructures, we determine the quantum
dot morphology and the in-plane components of externally induced strain tensor
at the quantum dot positions. Based on these experimentally determined
parameters, we calculate the strain-dependent excitonic emission energy, degree
of linear polarization, and fine-structure splitting using a combination of
eight-band formalism with multiparticle corrections using
the configuration interaction method. The presented experimental observations
are quantitatively well reproduced by our calculations