Tunneling in high-Tc superconductor/semiconductor heterostructure formed on Nb-doped SrtiO3

Abstract Superconductor/semiconductor tunnel junctions were fabricated by depositing BaYCuO films on Nb-doped SrTiO 3 substrates. Capacitance measurements on Au/ and BaYCuO/Nb-doped SrTiO 3 diode showed that low-dielectric-constant surface layers formed on the SrTiO 3 . The surface layer acted as tunnel barrier in the BaYCuO/Nb-doped SrTiO 3 diode, and the diode exhibited asymmetric conductance versus voltage characteristics caused by tunneling between the superconductor and the conduction band of SrTiO 3 .