Shot noise spectroscopy on a semiconductor quantum dot in the elastic and inelastic cotunneling regimes

We report shot noise spectroscopy on a semiconductor quantum dot in a cotunneling regime. The dc conductance measurements show clear signatures of both elastic and inelastic cotunneling transport inside a Coulomb diamond. We observed Poissonian shot noise with the Fano factor F approximate to 1 in the elastic cotunneling regime, and super-Poissonian Fano factor 1 < F < 3 in the inelastic cotunneling regime. The differences in the value of the Fano factor between elastic and inelastic processes reveal the microscopic mechanisms involved in the cotunneling transport. DOI: 10.1103/PhysRevB.87.041302