YBCO grain boundary Josephson junction coupled with a slot dipole antenna for terahertz wave detectors

11th European Conference on Applied Superconductivity

Yamada, H.^1 ; Hayasaka, T.^1 ; Toya, G.^1 ; Saito, A.^1 ; Ohshima, S.^1 ; Nakajima, K.^1

Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata

992-8510, Japan^1

关键词: Benzocyclobutene;    Coupling efficiency;    Junction parameters;    Micro-bridge;    Radio frequency waves;    Slot dipole antenna;    System sensitivity;    Ybco grain boundary josephson junctions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/4/042048/pdf
DOI  :  10.1088/1742-6596/507/4/042048

来源: IOP

【 摘 要 】

We examined terahertz wave detectors that used YBa2Cu3O7-δ(YBCO) grain boundary Josephson junctions (GBJJs) coupled with a slot dipole antenna (SDA). The detectors consisted of a 220-GHz full-wavelength SDA patterned on a Au layer and a GBJJ patterned on an YBCO/bicrystal MgO film, which were separated by an insulating benzocyclobutene layer. The microbridge of the fabricated junction was 5-μm wide and was trimmed to 2 μm using an ultraviolet laser cutter to modify the junction parameters. The critical current IC, normal resistance RN, and ICRNproduct after the trimming at 30 K were 0.62 mA, 1.42 Ω, and 0.88 mV, respectively. The current-voltage characteristics and radio frequency (RF) wave responses of these detectors for a millimeter wave of 180-240 GHz were measured at 30 K. The coupling efficiency between the GBJJ and the SDA and the system sensitivity were obtained as -19.0 dB and 630 V/W, respectively, at 193 GHz. For the RF wave response of 180-240 GHz, the coupling efficiency was relatively flat.