Schottky barrier and attenuation length for hot hole injection in nonepitaxial Au on p-type GaAs

Ballistic electron emission microscopy (BEEM) was performed to obtain current versus bias characteristics of nonepitaxial nanometer-thick Au on p-type GaAs in order to accurately measure the local Schottky barrier height. Hole injection BEEM data were averaged from thousands of spectra for various Au film thicknesses and then used to determine the attenuation length of the energetic charge carriers as a function of tip bias. The authors report an increase in attenuation length at biases near the Schottky barrier, providing evidence for the existence of coherent BEEM currents in Schottky diodes. These results provide additional evidence for the conservation of the parallel momentum of charge carriers at the metal–semiconductor interface.