Temperature dependent activation energies of exciton states on a single GaAs laterally coupled-quantum-dot molecule and quantum dot

Abstract

The objective of this study was to perform spectroscopy measurements of a single GaAs laterally coupled quantum dot molecule and quantum dot. Compared to photoluminescence spectra between a single GaAs laterally coupled quantum dot molecule and a single quantum dot, the presence of optical coupling was confirmed through dipole-dipole interactions in a single coupled quantum dot molecule. Based on temperature dependence measurements, weak exciton-phonon interactions (25 meV) were observed from the ground exciton state of a single GaAs laterally coupled quantum dot molecule in comparison with a strong exciton-phonon interaction (49 meV) from the ground exciton state of a single GaAs QD. Such weak interactions were due to reduced confinement at exciton states in a single laterally coupled quantum dot molecule. In addition, weaker activation energy (∼15 meV) was observed in terms of confined electrons in a single laterally coupled quantum dot molecule, where a confinement effect became reduced due to enlarged dimensional area in one direction along [1 1‾ 0].