Ballistic electron emission microscopy in liquid helium using low dimensional collector electrodes

Abstract

We report ballistic electron emission microscopy (BEEM) studies which show that a GaAs/AlGaAs heterostructure provides a very efficient collector electrode at 4.2 K. The enhanced thermal resolution at low temperature is utilized to determine the BEEM current threshold behavior very accurately. We find that diffusive scattering processes dominate the carrier transport across the Au/GaAs interface. Quantum wire regions on laterally structured samples are clearly identified with BEEM. The BEEM current is strongly enhanced on top of the quantum wires.