Quantum dot electrons as controllable scattering centers in the vicinity of a two-dimensional electron gas

Self-assembled InAs quantum dots can be controllably charged with a defined number of electrons per dot. We report on conductivity measurements of Al x Ga1−x As/GaAs heterostructures, where such quantum dots are embedded in the direct vicinity of a two-dimensional electron gas (2DEG). We demonstrate the controlled enhancement of the scattering rate in the 2DEG induced by charging the quantum dots with additional electrons. The resulting transport lifetimes are in good agreement with theoretical values for Coulomb scattering in two dimensions.