Phonon and Plasmon Interactions in Metal-Semiconductor Tunneling Junctions

Reproducible metal-semiconductor tunnel junctions are made on degenerate semiconductor single crystals whose surfaces have been cleaned by etching and then heating the samples in vacuum. This technique has been successfully used on GaAs, GaSb, and CdS. Detailed tunneling spectra are presented on the above-mentioned semiconductors and also on degenerate Sn${\mathrm{O}}_2$. In addition, some of the metal-semiconductor junctions have been intentionally doped with molecular impurities. No identifiable vibrational spectra of the molecules are observed.