Inelastic scattering in electron transport from a metal tip through a nanoscale metal cluster into a GaAs substrate

A scanning-tunneling-microscope (STM)-induced light emission technique was used for nanoscale metallic Ag clusters on a GaAs(1 1 0) surface at 100 K to study the inelastic scattering process of electrons at a metal/semiconductor interface. The study is based on the fact that the number of ballistic electrons propagating through a Ag/GaAs interface is proportional to the light intensity caused by radiative recombination in a GaAs substrate. A light intensity map as a function of the tip position shows that many of the electrons are inelastically scattered when passing through the metallic Ag cluster. The technique is useful for nanoscale characterization of future electronic and spintronic devices that have a metal/semiconductor interface.