A study of the electrical contact between YBa2Cu3O7 and some semiconductors

Most metals, when deposited on the high-temperature superconductor YBa2Cu3O7, lead to the oxygen depletion of the superconductor surface, which results in the formation of a nonsuperconducting layer near the 123 surface. The objective of the study was to fabricate and investigate the S/123 electrical contact, where S is a highly doped semiconductor, such as Pb(0.8)Sn(0.2)Te, GeTe, and Cu(2-x)Se, or a semimetal (e.g., Bi or Sb). Contacts of reasonably good quality with reproducible characteristics were fabricated by mechanical compression of the contact materials. An analysis of the results obtained demonstrates the possibility of producing semiconductor-high-temperature superconductor tunnel contacts with nonlinear resistance properties.