Direct Observation of Quasi-Bound States and Band-Structure Effects in a Double Barrier Resonant Tunneling Structure Using Ballistic Electron Emission Microscopy

Ballistic electron emission microscopy (BEEM) has been used to study transport in a double barrier resonant tunneling structure. Unlike conventional transport techniques, BEEM allows the injected electron energy to be varied independent of the band profile. We report the observation of quasi-bound states and band-structure effects as deduced from the temperature evolution of the BEEM spectra. The BEEM thresholds are found to be in good agreement with the calculated energetically favorable levels. Our results show that BEEM is a powerful spectroscopic tool for studying quantum structures.