Effects of alloy intermixing on the lateral confinement potential in InAs∕GaAs self-assembled quantum dots probed by intersublevel absorption spectroscopy

Abstract

The effect of thermal annealing on the conduction band states in self-assembled quantum dots has been investigated using far-infrared absorption spectroscopy. Broadening of the absorption linewidth associated with the ground state (s) to first excited state (p) transitions indicates that annealed quantum dots become less uniform in the lateral direction but more uniform in the growth direction as evidenced by photoluminescence measurements. A significant decrease in the s to p transition energy and the p-state splitting has been observed upon annealing. The avoided crossing as the transition energy approaches the optical phonon energy provides evidence of strong electron-phonon coupling in quantum dots.