Electronic coupling effects in self-assembled InAs quantum dots

Electronic coupling effects in self-assembled InAs quantum dots are investigated using capacitance and far-infrared (FIR) spectroscopy. Coupling between different dot-layers is studied using capacitance spectroscopy on samples with double-layers of vertically aligned quantum dots. A strong electrostatic dot-dot interaction reveals itself in distinct shifts of the many particle ground state energy. The fact that the line widths of the FIR resonances are typically a factor of 3 narrower than expected from the inhomogenous broadening due to size fluctuations of the dots is attributed to lateral coupling between the dots within the plane of the dot ensemble. (C) 1998 Elsevier Science B.V. All rights reserved.