Angle dependence of transmission probability of incident electrons into thin oxide films and noise spectra

We present the wave number vector dependence of transmission current and no ise spectra which was generated by the transition of electrons from vacuum to thin oxide films on metal electrodes. The transmission probability of an incident electron consists of three factors: (1) probability from vacuum t o the surface electronic states on the oxide film; (2) probability from the oxide film to the metal substrate; and (3) probability of the direct trans ition from vacuum to the metal substrate. The noise spectra were proportion al to the duration of the electron hopping, which contained two types of wa ve number dependence. One was spot-type-noises, which were related to the l attice defects, and another was smoothly distributed noise which suggested randomly distributed surface defects. (C) 2000 Elsevier Science S.A. All ri ghts reserved.