VARIATION OF THE JOSEPHSON CURRENT WITH CARRIER CONCENTRATION IN THE BARRIER

A phenomenological investigation of the de Josephson current in superc onductor- (S-) normal-metal-(N) [semiconductor- (Sm-)] superconductor junctions is carried out as a function of the carrier concentration in the barrier. The occurrence of a nonmonotonic dependence of the Josep hson current on the carrier concentration is predicted within some lim its. This study suggests that in S-N- (Sm-) S structures there is an o ptimum carrier concentration range which gives the maximum value of th e Josephson current I-C and the junction parameter l(C)R(N).