Transport of 75-1000 eV electrons in metal-insulator-metal devices

Metal-insulator-metal nanostructures with a 50 nm silver film and a 30 nm aluminum film separated by a few nanometer insulator layer (aluminum oxide) are irradiated with a focused e−-beam (diameter ≤500 μm) with kinetic energies in the range of 75-1000 eV. Impact angle and energy dependence of the e−-beam induced electron emission from oxide covered aluminum and from silver show a good coincidence with previous results. The e−-beam induced internal device current measured between the aluminum and the silver film, on the other hand, is found to be independent of the primary electron energy and impact angle. The results suggest that external electron emission may have to be included in the interpretation of the internal transport currents.