Single-electron tunneling force spectroscopy of an individual electronic state in a nonconducting surface

A tunneling spectroscopy technique to measure the energy level of an electronic state in a completely nonconducting surface is demonstrated. Spectroscopy is performed by electrostatic force detection of single-electron tunneling between a scanning probe and the state as a function of an applied voltage. An electronic state near the surface of a SiO2 film is found 5.5 +/- 0.2 eV below the conduction band edge. A random telegraph signal, caused by sporadic back-and-forth single-electron tunneling, is observed as the probe Fermi level passes through the state energy. (c) 2006 American Institute of Physics.