Single electron tunneling detected by electrostatic force

Single electron tunneling events between a specially fabricated scanning pr obe and a conducting surface are demonstrated. The probe is an oxidized sil icon atomic force microscope tip with an electrically isolated metallic dot at its apex. A voltage applied to the silicon tip produces an electrostati c force on the probe, which depends upon the charge on the metallic dot. Si ngle electron tunneling events are observed in both the electrostatic force amplitude and phase signal. Electrostatic modeling of the probe response t o single tunneling events is in good agreement with measured results. (C) 2 001 American Institute of Physics.