Investigation of the electronic properties of Au nanoclusters in SiO2 by combined scanning tunneling/atomic force microscopy
The tunneling of electrons through Au nanoc lusters formed by pulsed laser deposition in a SiO2 thin film on a Si substrate has been investigated by combined scanning/atomic force microscopy (STM/AFM). Conducting Pt-coated Si cantilevers were used. The feedback was maintained via the AFM channel, and the current-voltage (I-V) characteristics of the tunnel contact between the AFM probe and the n+-Si substrate through a =4-nm-thick SiO2 film with Au nanoclusters =2 nm in diameter were measured simultaneously. The current image of the structure contained areas of increased current (tunnel-current channels) 2–15 nm in size, related to tunneling of electrons through Au nanoclusters in SiO2. The I-V characteristics recorded in the tunnel-current channels exhibit specific features related to the Coulomb blockade of electron tunneling through Au nanoclusters.