Exciton acoustic–phonon coupling in single In_0.4Ga_0.6As/GaAs quantum rings

Abstract

Coupling of acoustic phonons to excitons in small In0.4Ga0.6As/GaAs quantum rings (QRs) is investigated. The temperature dependence on the spectral distribution of the excitonic single QR luminescence is presented and discussed. The contributions of piezoelectric and deformation potential couplings are specified. We find that QR spectra exhibit non‐Lorentzian line shapes including sharp zero‐phonon lines with broad backgrounds induced by acoustic phonons couplings. The latter are strongly temperature dependent. Coupling via the deformation potential mechanism is found to have the dominant contribution. This involves more energetic phonons and leads to sideband broadenings. Phonons that contribute to piezoelectric coupling have low energies. Their impact is in close proximity to the zero‐phonon line (ZPL) peak.