Biased GaAs/AlGaAs superlattices employed as energy filter for ballistic electron emission microscopy

In this work, buried Al0.4Ga0.6As/GaAs superlattices are employed as an energy filter in order to study the energy distribution of the ballistic electron current in ballistic electron emission microscopy (BEEM). As the measured total transmission of the superlattice is in excellent agreement with the calculated transmission, the superlattice is a promising tunable energy filter for studying the energy distribution of ballistic electrons. We further show that due to the large difference in electron masses between the Au base layer and the GaAs collector, parallel momentum conservation leads to considerable electron refraction at the Au/GaAs interface. As a consequence, the energy distribution of ballistic electrons is inverted beyond the Au/GaAs interface.