Hot-Electron Transfer through Thin-Film Al–Al2O3 Triodes

Triode devices, consisting of Al–Al2O3–Al–Al2O3–Al films, were used to inject hot electrons into an oxide film. Transmission ratios were measured as a function of collection-oxide thickness, collection bias, and injection at 77° and 300°K. These data were compared with a model for hot-electron penetration in which electron-electron interactions in the metal were invoked, with a mean free path le∝ (ε−εf)−2; once-scattered electrons were included in the collected fraction. Assuming an energy loss of 0.1 eV per interaction in the oxide (from optical absorption data), the comparison of the model and the experimental data yielded a mean free path between these interactions of approximately 12 Å. The predicted transmission ratios agreed quite well with the experimental data.