COULOMB INTERACTION CONTROLLED ROOM-TEMPERATURE OSCILLATION OF TUNNELCURRENT IN POROUS SI

A novel phenomenon of regular oscillations is observed in I-V characte ristics of porous silicon under illumination by visible light, The mea surements are performed at room temperature using a scanning tunneling microscope. The heights of the oscillation peaks appear to be a linea r function of the oscillation number. The experimental value of the Co ulomb energy determined from the oscillation period is much smaller th an k(B)T. The oscillations are attributed to a Coulomb effect, i.e., t o the periodic trapping of a multielectron level in a quantum well wit hin a Si nanocrystal under the combined influence of the voltage varia tion at the STM tip and the Coulomb interaction among the carriers. (C ) 1998 American Institute of Physics.