| Nowadays terahertz (THz) technologies attract tremendous attention, however, the devices working at THz waveband are not well developed now. Because superconducting devices are sensitive to terahertz signal, the studies on superconducting detectors, oscillators and resonators are widely carried out. The single crystal Bi2Sr2CaCu2O8+x (BSCCO) is a strongly anisotropic superconductor with layered structure, which makes it a promising material for fabricating intrinsic Josephson junctions (IJJs) and THz signal controlling devices. In this thesis, I will introduce my studies in the following aspects:1. The double-sided fabrication process was adopted to fabricate small scale IJJs. The number of the junctions could be controlled under 10 and the scale of the junctions could be controlled to around 10μm2. Electrical transport characteristics were studied when the device was cooled down to liquid helium temperature, and the I-V curve showed that the junctions had coherent scale. Furthermore, electrical transport characteristics and 100 GHz signal response of the IJJs were studied with a magnetic field subjected along c-axis direction. When the device was tested under the magnetic field, the critical current was suppressed to 40 times lower than that without the magnetic field. Furthermore, we successfully observed the current steps, and the position of the step agreed with AC Josephson effect. 2. Large scale mesa style IJJs were fabricated for applications of THz oscillator. On the base of the improvement of photolithography and etching fabrication, we fabricated mesa structured devices with coherent scale. I made a detailed study on the rectangle device with a scale of 330×50×1μm3. THz signal was successfully detected at the temperatures from 12 K to 55 K, the frequencies of the signal varied from 450 GHz to 750 GHz. At certain temperatures, the signal can be detected when the device was high-biased and low-biased, and the signal detected in high-biased area was much stronger than that in low-biased area. Furthermore, the frequencies of the signal could be tunable when the biasing voltage was adjusted within certain range. This result provides a possibility of fabricating voltage-tunable THz emitter.3. Layered superconducting THz metamaterial was fabricated using BSCCO crystal. We fabricated ELC resonator units with a repeating distance of 60μm on a 2 mm×2 mm BSCCO flake. The device was tested using terahertz time domain spectroscopy (THz-TDS) and a resonance mode was observed at about 400 GHz.4. Fabrication of the IJJs using argon ion milling was systematically studied. We tested and analyzed the etching rate under different accelerating voltages and incident beam angles, after which we got an etching method with high etching rate and low damage to the devices. The potential factors which could influence the shape of the step-profile were also discussed. Our study proved that with low accelerating voltages (about 150 V) and incident beam angle of 45°, the etching rate could be high and the damage to the devices and photo resist could be reduced. Furthermore when we etched with an incident beam angle of 45°, the re-deposition could be reduced which could make a sharper step-profile.
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