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

TL;DR

This study uses ballistic electron emission microscopy to measure local Schottky barrier heights and attenuation lengths for hot hole injection in non-epitaxial gold on p-type GaAs, revealing coherence effects at the interface.

Contribution

It provides the first nanoscale measurements of attenuation length variations near the Schottky barrier in non-epitaxial metal-semiconductor contacts, demonstrating coherent charge carrier transport.

Findings

Attenuation length increases near the Schottky barrier bias.

Evidence of coherent BEEM currents in Schottky diodes.

Challenges the idea of momentum randomization at the interface.

Abstract

Ballistic electron emission microscopy (BEEM) was performed to obtain nanoscale current versus bias characteristics of non-epitaxial Au on p-type GaAs in order to accurately measure the local Schottky barrier height. Hole injection BEEM data was averaged from thousands of spectra for various metal film thicknesses and then used to determine the attenuation length of the energetic charge carriers as a function of tip bias. We report the marked 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 against the randomization of a charge carrier's momentum at the metal-semiconductor interface.