Probe and control of the reservoir density of states in single-electron devices

We present a systematic study of quasi-one-dimensional density of states (DOS) in electron accumulation layers near a Si–SiO2 interface. In the experiments we have employed two conceptually different objects to probe DOS, namely, a phosphorus donor and a quantum dot, both operating in the single-electron tunneling regime. We demonstrate how the peaks in DOS can be moved in the transport window independently of the other device properties, and in agreement with the theoretical analysis. This method introduces a fast and convenient way of identifying excited states in these emerging nanostructures.