Thick Bi₂Sr₂CaCu₂O_8+δ films grown by liquid-phase epitaxy for Josephson THz applications

Theoretical and experimental studies of intrinsic Josephson junctions (IJJs) that naturally occur in high-T _c superconducting Bi₂Sr₂CaCu₂O_8+δ (Bi-2212) have demonstrated their potential for novel types of compact devices for the generation and sensing of electromagnetic radiation in the THz range. Here, we show that the THz-on-a-chip concept may be realized in liquid-phase epitaxial-grown (LPE) thick Bi-2212 films. We have grown μm thick Bi-2212 LPE films on MgO substrates. These films display excellent c-axis alignment and single crystal grains of about 650 × 150 μm² in size. A branched current–voltage characteristic was clearly observed in c-axis transport, which is a clear signature of underdamped IJJs, and a prerequisite for THz-generation. We discuss LPE growth conditions allowing improvement of the structural quality and superconducting properties of Bi-2212 films for THz applications. (paper)