Theory of Inelastic Electron-Surface-Plasmon Interactions in Metal-Semiconductor Tunnel Junctions

The excess tunneling current due to electron-surface-plasmon interactions in semiconductor-metal tunnel junctions is calculated. The expression for the second derivative of this excess current, which corresponds to structure in $\frac{d^{2}I}{d{V}^2}$ as an increase in conductance at bias voltages near the surface plasmon energy in the semiconductor, agrees with experiment both in magnitude and line shape.