CARRIER REFLECTION AT THE SUPERCONDUCTOR-SEMICONDUCTOR BOUNDARY OBSERVED USING A COPLANAR-POINT-CONTACT INJECTOR

The Andreev reflection of carriers at the boundary between a superconductor and a semiconductor has been studied buy measurement of the differential resistance of a n-type-SiNb point contact with a coplanar structure. The boundary condition of the pair potential in the Si-Nb proximity system is obtained from these measurements. A carrier-concentration dependence of the pair potential at the boundary is observed. The pair potential in the Si at the boundary increases with increasing carrier concentration. © 1990 The American Physical Society.