Light-induced conductance resonance in ultrasmall Si nanoparticles

Ultrasmall, uniform-size (similar to 1 nm) Si nanoparticles, dispersed from p-type boron-doped silicon, are reconstituted on a Si substrate. Electronic transport processes are studied by current-voltage spectroscopy at room temperature, using scanning tunneling microscopy, in a two-terminal configuration, under both dark conditions and light illumination. Unlike the dark conditions, we observe, under light irradiation, for negative tip biasing, a regular structure at similar to 1.0 eV period. The series is discussed in terms of light-induced hole states that otherwise are highly infrequent in ultrasmall Si particles, under standard low doping. (C) 2000 American Institute of Physics. [S0003-6951(00)00237-0].