A three terminal device with the Al/Al2O3/(Ba, Rb)BiO3/Nb-doped SrTiO3
structure was fabricated using a superconducting base layer. The stab
le interface between (Ba,Rb)BiO3 and the artificial oxide barrier was
obtained using in situ Al2O3 deposition. The output characteristics we
re measured as functions of input current. A current gain greater than
2 was obtained in the common emitter configuration.