Chi-Lun Jiang

Manifestation of the quantum size effect in transmission resonance

The transmission probability of the free electron scattered by the quantum well in metal film may reveal the phenomenon of resonance. This transmission resonance, appearing above the vacuum level, can be probed by scanning tunnelling spectroscopy (STS). In this paper, STS is used to observe the transmission resonance on Ag films grown on Si(111)7 × 7 surfaces. The transmission resonance appears at different bias voltages in the spectra depending on the film thickness; its energy level moves toward the vacuum level with increasing film thickness. When the film is thick enough, transmission resonance can occur twice in the biasing voltage range, and the energy separation between the resonances decreases with increasing film thickness. The existence of transmission resonance affects the contemporary standing wave states (SWS) and, in general, pushes the following SWS to higher energies.