Local photon emission of self-assembled metal nanoparticles

The tip of a scanning tunneling microscope (STM) may be used as an extremel y localized source of low-energy electrons to locally excite photon emissio n from a variety of metal films. The detection of locally excited luminesce nce at the junction of a STM tip provides access to electron dynamic proper ties at the surface, which makes it possible to study luminescence phenomen a of nanometer-sized structures. We analyzed maps of the photon intensity emitted from electrically isolated silver nanoparticles self-organized as a 2D network on a gold (111) substr ate. We observed unexpectedly strong variations of photon-emission efficien cy from isolated nanoparticles depending on how tightly they are embedded w ithin the network site. The quenching site observed in the STM photon emiss ion map is interpreted as an enhanced interaction of electrons with surface phonon modes. (C) 2000 Published by Elsevier Science B.V.