Optical transition and carrier relaxation in a type-II InAs/GaAsSb quantum dot layer

Abstract

In-plane ultrahigh-density InAs quantum dots (QDs) were grown on the GaAsSb buffer layer by molecular beam epitaxy. Photoluminescence (PL) properties of the InAs QDs/GaAsSb layer were measured under 1.58 eV and 1.44 eV light excitations, which were GaAs and InAs QD/wetting layer (WL)/GaAsSb excitations. For the GaAs excitation, PL spectra were due to a type-II transition from the ground state (GS) of the QD conduction band to the GaAsSb valence band. This PL spectrum did not depend on the measurement position because of the electron filling into lower GS levels. For the InAs QD/WL excitation, PL spectra originated from the crossed transitions of localized bound excitons between QD excited states (ES) and the WL valence band, and depended on the measurement position. Furthermore, excitation power and temperature dependences of the PL spectra were measured to discuss carrier dynamics.

Quantum Dot Phase Transition Simulation with Hybrid Quantum Annealing via Metropolis-Adjusted Stochastic Gradient Langevin Dynamics

“…e in-plane ultrahigh-density ((0.5 ∼ 1 × 10 12 cm − 2 ) InAs QDs layer was grown on a GaAsSb buffer layer and an InAsSb wetting layer (WL) on GaAs (001) substrates by molecular beam epitaxy (MBE). Detailed information regarding the experimental conditions and growth procedure can be found in literature [21]. Photoluminescence (PL) properties of this type-II heterostructure of high-density InAs QDs/GaAsSb were measured by using a time-resolved micro-PL system including an InGaAs avalanche photodiode (APD) and an InGaAs diode array.…”

InAs/GaAsSb in-plane ultrahigh-density quantum dot lasers

“…X-ray diffraction measurements were used to estimate that the Sb composition of the GaAsSb buffer layer was 12%-14%, which is very close to a type-II band alignment of GaAsSb/InAs hetero-interface. 25) Figure 1(b) shows an atomic force microscopy (AFM) image of InAs QDs on the GaAsSb/GaAs(001). The in-plane density of the InAs QDs was about 5 × 10 11 cm −2 .…”