Structural and optical properties of vertically stacked triple InAs dot-in-well structure

The authors report a detailed investigation of the structural and optical properties of vertically stacked InAs quantum dots embedded in an (In,Ga)As quantum well by means of transmission electron microscopy and time resolved photoluminescence based on the upconversion technique. By comparing the optical features of quantum dot samples of different barrier thicknesses (nominal values between 5 and 65 nm), they have found evidence for electronic coupling among the quantum dots, featured by an increase of radiative lifetime and a relatively blueshifted emission peak for the thinnest spacer layer sample.