LOW-TEMPERATURE BEHAVIOR OF HIGH-T-C SUPERCONDUCTOR SEMICONDUCTOR HETEROJUNCTIONS

The transport mechanisms of p-type YBa2Cu3O7-delta/n-type Si heterojun ctions were determined in the temperature range 10 K less than or equa l to T less than or equal to 300 K by current-voltage measurements. Th e knowledge of these mechanisms is of great importance for studies and applications of superconductor/semiconductor contacts. For T > T-c, t he junction behaves as a Schottky contact with several transport mecha nisms occurring simultaneously. The main mechanisms in the temperature ranges 200 K less than or equal to T less than or equal to 300 K and T-c less than or equal to T less than or equal to 200 K are thermoioni c field emission and the multistep-tunneling-mechanism, respectively. Tunneling of Copper pairs besides quasiparticles dominates in the temp erature range T < T-c. The contact resistance measures to about 10(3) Omega cm(2) at room temperature. The investigated contacts show a bett er diode characteristic for T < T-c than for T > T-c.