Optical switching of single-electron tunneling in SiO2/molecule/SiO2 multilayer on Si(100)

Porphyrin-based molecules inserted into the oxide layer of a metal-oxide-semiconductor structure served as Coulomb islands. A Coulomb staircase originating from the single-electron tunneling was observed in a current-voltage curve. We found that light irradiation induced a shift in the Coulomb staircase. This shift was reversible; the shifted Coulomb staircase returned to its original position when the light irradiation was turned off. We thus demonstrated optical switching of a tunneling current. This result indicates that the molecular Coulomb islands have the potential to provide a range of optical functionality in single-electron tunneling devices. (C) 2004 American Institute of Physics.