Observation of Photon-Assisted Tunneling through a Quantum Dot

Abstract
We have measured dc transport through a GaAs/AlGaAs quantum dot in the presence of a microwave signal of frequency f. We find features related to the photon energy hf whose positions in gate voltage are independent of the microwave power buy vary linearly with frequency. The measurements demonstrate photon-assisted tunneling in the mesoscopic regime. A comparison is made with a model that extends Coulomb blockade theory to include photon-assisted tunneling.