Development of high temperature superconducting terahertz emitters with high power and narrow line width

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02590
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28050:Nano/micro-systems-related
• Research Institution: University of Tsukuba
• Principal Investigator: Kashiwagi Takanari 筑波大学, 数理物質系, 講師 (40381644)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 高温超伝導 / ジョセフソン接合 / テラヘルツ波 / 単結晶

Outline of Final Research Achievements

In order to develop device characteristics of high temperature superconducting terahertz emitters such as emission power and radiation line width, we have studied the relationship between crystal characteristics of Bi2212 single crystals and the emitting device electric characteristics. As the result of the study, it became clear that the annealing condition to adjust the amount of the excess oxygen in the crystals strongly depends on the crystal growth condition of the ratio of Bi and Sr. In particular, as for device fabrication, the oxygen contents of the surfaces of the crystal prepared under over doped condition are very sensitive for the heat treatment such as evaporation process of the metallic thin films. They become small by evaporation process. These results give us a guide for the approval crystal preparation for the high performance terahertz emitting devices.

Free Research Field

超伝導工学

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた成果は，これまで高温超伝導体Bi2212単結晶を用いたテラヘルツ波発振素子としてあまり細かな点が調べれていない材料特性の傾向を捉えることができた点で学術的意義がある。またその材料特性とデバイス特性の相関についてもある程度の傾向を捉えることができた点も学術的に新しい情報を示すことが出来た。また，テラヘルツ帯の電磁波は，今後益々発展が期待される情報化社会や高度なセキュリティー社会において欠かすことができない。本研究成果は将来的にこのような分野の発展にフィードバックすることが強く期待できる点において社会的意義がある。