JUNCTION CHARACTERISTICS OF AN AU/BA1-XKXBIO3/NIOBIUM-DOPED SRTIO3 STRUCTURE

Au/Ba1-xKxBiO3 and Ba1-xKxBiO3/niobium-doped SrTiO3, two types of junctions which correspond to the emitter base and base collector in superconducting base transistors, respectively, have been fabricated and studied. The highest T(c) end point (T(c0)) of 28 K was obtained of thin film Ba1-xKxBiO3 by rf-sputtering method. The Au/Ba1-xKxBiO3 tunnel spectrum showed a clear gap structure and was very close to the ideal Bardeen Cooper Schrieffer theory's (BCS) form with DELTA(0)=3.19 meV. The Ba1-xKxBiO3/SrTiO3(Nb) junction with heavy niobium doping (0.1 wt%) showed tunnellike I-V characteristics. The dI/dV spectrum for a high-T(c) superconductor/semiconductor junction displayed the energy gap structure of a superconductor.