Surface plasmon polariton-assisted electron emission and voltage-controlled negative resistance of Al-Al2O3-Au diodes

Electrons are ejected from an Au surface when their energy exceeds the work function of Au, phi(Au), which is 5.2 eV. The threshold voltage for the onset of electron emission from Al-Al(2)O(3)-Au diodes that develop voltage-controlled negative resistance in their current-voltage characteristics is V(EM) congruent to 2.4 V. The threshold voltage for electroluminescence (EL) is V(EL) = 1.6-2.0 V. The interaction of electrons with surface plasmon polaritons (SPPs) produced at the Al(2)O(3)-Au interface by EL photons provides a mechanism by which electrons gain enough energy to surmount the work function barrier at the Au-vacuum interface when the applied voltage is less than 5.2 V. The interaction of EL photons with surface plasmons in Au is a new mechanism for creating SPPs. (C) 2010 American Institute of Physics. [doi:10.1063/1.3407510]