Low-temperature behaviour of high-Tc superconductor/semiconductor heterojunctions

Abstract The transport mechanisms of p-type YBa 2 Cu 3 O 7− δ / n -type Si heterojunctions were determined in the temperature range 10 K ≤ T ≤ 300 K by current-voltage measurements. The knowledge of these mechanisms is of great importance for studies and applications of superconductor/semiconductor contacts. For T > T c , the junction behaves as a Schottky contact with several transport mechanisms occurring simultaneously. The main mechanisms in the temperature ranges 200 K ≤ T ≤ 300 K and T c ≤ T ≤ 200 K are thermoionic field emission and the multistep-tunneling-mechanism, respectively. Tunneling of Copper pairs besides quasiparticles dominates in the temperature range T T c . The contact resistance measures to about 10 3 Ω cm 2 at room temperature. The investigated contacts show a better diode characteristic for T T c than for T > T c .