RAMAN-SCATTERING AS A PROBE OF THE SUPERCONDUCTING PROXIMITY EFFECT

Temperature-dependent Raman spectroscopy is used to investigate the ef fect of superconductivity on the near-surface electronic structure of a semiconductor in good electrical contact with a superconductor. The light scattering is performed through a high-quality thin (60-100 Angs trom) film of Nb, grown directly onto in-situ Ar+-etched (100)-n(+)InA s. Below T-c, the LO mode, associated with the surface charge accumula tion layer in the InAs, is enhanced by similar to 40% in comparison wi th the nearby L_ bulk phonon mode. This change, reversible upon temper ature cycling, is observed only when the Nb is in good electrical cont act with the InAs. Preliminary results show a similar effect on NbN/In As. Our results constitute the first optical detection of the supercon ducting proximity effect.