SURFACE-PLASMON ASSISTED ELECTRON PHOTON INTERACTION IN METAL-OXIDE METAL LAYERED STRUCTURES

A state of art survey is given of the electron-photon interaction in planar metal-oxide-metal (MOM) tunnel diodes both from the theoretical and experimental points of view. Light emission and internal photoeffect experiments are overviewed and a phenomenological model is proposed for the electron-photon interaction in order to explain the observed phenomena. The internal photoeffect is assumed to be a fast mode surface plasmon assisted process, whereas in light emission slow mode plasmons, which propagate along the barrier region, are thought to play an important role. The efficiency of the slow mode --> fast mode transformation has been estimated to be approximately 10(-3), using experimental data. The existence of the slow mode, however, has not yet been proved experimentally in a direct way, i.e. with a dispersion measurement. Nevertheless, theoretical predictions and some experimental indications suggest that it plays an important role in the electron-photon interaction not only in simple devices, but also in multilayer MOM structures.