Ballistic electron emission microscopy on buried GaAs-AlGaAs superlattices

In Ballistic Electron Emission Microscopy, ballistic electrons are injected from a metallic base contact into a semiconductor. In this experiment, the miniband of a GaAs-AlGaAs superlattice is employed as energy filter in order to study the energetic distribution of the ballistic electrons injected into the semiconductor. It is found, that due to the large difference in electron mass between Au and GaAs, parallel momentum conservation leads to considerable electron refraction at the Au-GaAs interface. Moreover, a resonant tunneling structure directly at the sample surface can act as momentum filter for electrons injected at k∥=0.