用于电压基准的Nb／NbxSi1—x／Nb约瑟夫森单结的研制

摘要

The core device of Modern programmable Josephson voltage standard is Josephson junction array. The most advantageous Josephson junction array is Nb/NbxSi1-x/Nb material array. The advantages of Nb/NbxSi1-x/Nb material Josephson junction are that three-layer film production process is simple, Nb and NbxSi1-x etching processes are the same and NbxSi1-x potential barrier layer components can be easily adjusted. In this paper, we investigate the NbxSi1-x/Nb single Josephson junction in National Institute of Metrology. Through measuring the dc current-voltage characteristics under low temperature （4.2 K）, superconducting tunneling current and a zero voltage state jumping to voltage state are observed clearly, finally the measurement results are discussed. The work is the first study on Nb/NbxSi1-x/Nb single Josephson junction in China.%现代可编程约瑟夫森电压基准的核心器件是约瑟夫森结阵.目前最具有优势的约瑟夫森结阵是 Nb/NbxSi1-x/Nb材料的结阵. Nb/NbxSi1-x/Nb材料的约瑟夫森结 具有三层薄膜的制作过程简便, Nb和NbxSi1-x刻蚀工艺相同以及NbxSi1-x 势垒层成分可调等优点.中国计量科学研究院设计制作了Nb/NbxSi1-x/Nb约瑟夫森单结. 通过在4.2 K低温下对所做单结进行直流电流-电压特性测量,观测到了清晰的超导隧穿电流和 从零电压态向电压态的跳变,最后就测量结果进行了分析讨论.此项工作属于国内首个开展 Nb/NbxSi1-x/Nb材料约瑟夫森单结研究的工作.