Abstract
We have studied the variation with bias (to ± 150 mV) of the I, dV/dI, and d2I/dV2 of p‐type GaAs point contacts on Pb single crystals at liquid‐He temperatures. The results are examined and are compared with those obtained from p‐type GaAs–Pb film tunnel junctions fabricated by conventional techniques. A small reduction of the energy gap and a shift in bias energy of the phonon‐induced structure in the superconducting Pb tunneling characteristics have been observed, and we suggest these are due to pressure at the point contact. The effects of this pressure on the p‐type GaAs tunneling characteristics are also observed and some qualitative explanations are suggested.