Tunneling Spectroscopy of CdS Schottky-Barrier Junctions

Schottky-barrier tunnel junctions have been fabricated on degenerate CdS by cleavage in high vacuum followed by evaporation of metal contacts. The background conductance of such junctions is found to be in satisfactory agreement with an exact one-electron-model calculation. Polaron effects, observed at biases corresponding to the LO phonon energy, appear to be qualitatively different from published results obtained for junctions on $n$-type GaAs where electron-phonon coupling is weaker. Zero-bias anomalies of the Appelbaum-Anderson type (conductance peaks) are observed and studied in high magnetic fields. The magnetic field dependence of these anomalies is found to be consistent with the Appelbaum-Anderson model of magnetic scattering as extended by Wolf and Losee. Large negative $g$ shifts of the localized moments are observed.