Enhancement of Optical Anisotropy by Interconnection Effect along Growth Direction in Multistacked Quantum Dots

Abstract

We report the enhancement of in-plane optical anisotropy in stacked InAs quantum dots (QDs) with a decrease in spacer layer thickness. The in-plane polarization anisotropy of photoluminescence intensity is basically due to the ellipsoidal QD shape caused by lattice mismatch strain. The polarization degree increases to approximately 40% with decreasing the spacer layer thickness. When the spacer layer thickness decreases, the electron envelope function becomes longer along the growth direction, which is the interconnection effect. This interconnection results in the enhancement of the in-plane anisotropy. These results exhibit that the vertical interaction by the interconnection effect is an important factor for the QD optical anisotropy.