films grown by liquid-phase epitaxy for THz applications*

Intrinsic Josephson junctions (IJJ) in the high-T_c superconducting Bi₂Sr₂CaCu₂O_8+δ (Bi-2212) exhibit the fundamental phenomena associated with the Josephson effect opening an avenue towards compact THz chip system with integrated Josephson plasma wave devices for THz applications. To realize the THz-on-a-chip concept, we have grown high-quality and thick epitaxial Bi-2212 films by liquid-phase epitaxy (LPE). The structural and stoichiometric characterizations of our best films by XRD and EDS confirm single-phase, highly c-axis aligned crystalline Bi-2212 films. Sharp superconducting transitions in transport measurements on annealed films occur at approximately 85K. In the c-axis transport measurements, we have observed strongly hysteretic I-V characteristics with relatively high J_c of 600 A/cm² which is a clear signature of underdamped IJJs and a prerequisite for THz generation. We will discuss LPE growth conditions allowing to improve the size of single phase Bi-2212 grains and their structural and superconducting properties for leading to the THz-on-a-chip systems.