Study On Current-Voltage And Radiation Characteristics Of HTS Intrinsic Josephson Junctions

High temperature superconducting (HTS) intrinsic Josephson junctions (IJJs) not only have the advantages of low noise and wide tunable frequency, but also has the advantages of serial arrangement naturally formed in the high temperature superconductors, high energy voltage and working temperature at liquid nitrogen. These noted advantages make the IJJs to be potential millimeter and submillimeter wave solid state sources.The research work of this dissertation is based on Tl2Ba2CaCu2O8(T1-2212) HTS thin films and Bi2Sr2CaCu2O8(Bi-2212) single crystals. The current voltage characteristics (IVCs), millimeter wave radiation and terahertz radiaton are deeply studied and the main experimental results are shown as follows:1. By putting the misaligned T1-2212HTS IJJs in the Fabry-Perot resonator and use the resonating of the Fabry-Perot resonator, the coupling between the IJJs and the outer space is strengthened, and the millimeter wave radiation from the IJJs is realized.2. Fabricate misaligned T1-2212IJJs with good consistence. By analyzing the IVCs of the IJJs, the energy suppression and excess current phenomena are investigated. These phenomena are explained by the nonequilibrium effect due to high quasiparticle current density.3. By irradiating the misaligned T1-2212IJJs and adjusting its position in the Fabry-Perot resonator, a microwave induced step is observed on the IVCs. The response to different frequency and power indicates the microwave induced step is a subharmonic step.4. Study the IVCs of the misaligned T1-2212IJJs biased with a voltage source. The differences and similarities are compared with a current biased case. The temperature dependence of the IVCs confirms the existence of the unstability.5.(1) With Bi-2212mesa IJJs, terahertz emission above1THz is successfully observed.(2)With two Bi-2212mesas in series, the power dependence on IJJ number is studied by gradually mounting the height of the mesas. The results show that the largest emission power,-0.5μW, is gotten at0.708THz when there are740IJJs in each mesa.(3) Using Bi-2212IJJs with high critical temperature, terahertz emission is detected at82K and the frequency is about0.27THz.(4) Using parallel mesas in series and Gold-Bi-2212-Gold mesa structures, the way to improve the emission power is studied.