title: Low Temperature Photoluminescence Kinetics of Double-Ring Structured GaAs Quantum Dots.
abstract: This work is focused on spectroscopically characterizing kinetic properties of concentric quantum-ring complexes of GaAs quantum dots. Quantum-ring (or double-ring) GaAs quantum dots, embedded in an Al0.3Ga0.7As barrier layer, were grown by a droplet epitaxy method during molecular beam epitaxy on a GaAs (001) substrate. Emission peaks of photoluminescence spectra with different excitation power, were measured as 702 nm at 0.17 mW and 690 nm at 400 mW, were blue-shifted as the excitation power increased. In addition, excitation laser power dependence of time-resolved photoluminescence of double-ring GaAs quantum dots at 10 K under 400 nm excitation wavelength was performed, revealing that photoluminescence lifetime slowly decreased in comparison to that of single disc-like quantum dots as excitation power increased, implying that carrier transfer between inner ring and outer ring could slow down the decay process. The luminescence lifetime at 10 K increased from 245 to 409 ps in the range from 0.17 to 400 mW of excitation power.
authors.forename: Soung
authors.initials: S
authors.lastname: Myoung
authors.forename: Ok Mi
authors.initials: OM
authors.lastname: Mun
authors.forename: Sang-Youp
authors.initials: SY
authors.lastname: Yim
authors.forename: Jong Su
authors.initials: JS
authors.lastname: Kim