Design and characterization of single crystalline Bi-2223 mesas towards the observation of coherent terahertz radiation emitted from trilayer intrinsic Josephson junctions

Coherent and continuous terahertz electromagnetic radiation emitted from stacks of intrinsic Josephson junctions (IJJs) has been observed solely from a bilayer Bi-2212 system [L. Ozyuzer et al., Science vol. 318, p. 1291 (2007)]. In this study, we focus on a trilayer Bi-2223 system, which consists of triple superconducting copper oxide layers per unite cell. Since an optimally doped Bi-2223 crystal exhibits the superconducting critical temperature above 100 K, we can expect to obtain appreciable emissions at remarkably high operation temperatures. Here, we fabricate Bi-2223 rectangular mesas in a conventional manner using photolithography and argon ion milling techniques. Unfortunately, we have not yet succeeded in observing intense emission from Bi-2223 mesas. Nevertheless, there are indications that the trilayer Bi-2223 system differs essentially from the bilayer Bi-2212 system in terms of the c-axis interlayer coupling. In the poster, we will discuss the multiple quasiparticle branches seen in the current-voltage characteristics of the Bi-2223 mesas. We will also propose an improvement in the microfabrication processes so that we can obtain the intense emission signals from the Bi-2223 mesas.