Carrier reflection at the superconductor-semiconductor boundary observed using a coplanar-point-contact injector

Abstract
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-Si–Nb 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.