Fabrication of double mesa structures by E-beam lithography from high temperature superconducting Bi<inf>2</inf>Sr<inf>2</inf>CaCu<inf>2</inf>O<inf>8+δ</inf> (Bi2212) for powerful terahertz emission

Abstract

We work on a frequency tunable solid state device to meet the needs of continuous, coherent, powerful terahertz emission sources that fill practically important terahertz gap. High temperature superconducting (HTS) coherently oscillating Josephson junctions in Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212) crystal make this approach very promising. Since doping dependence of Bi2212 is an important parameter, Bi2212 crystals are annealed in vacuum or purified argon gas flow at 425 o C. For further processing we pattern both single and double rectangular mesa structures by using electron beam lithography on the cleaved surface of the crystal. Resistance-temperature (R-T), and current-voltage behavior (I -V) measurements achieved.