Abstract Nb/Al-AlOx/Nb tunnel junctions with controllable critical current density Jc are fabricated using the standard selective Nb etching process. Tunnel barriers are formed in different oxygen exposure conditions (oxygen pressure P and oxidation time t), giving rise to Jc ranging from 100 A/cm2 to above 2000 A/cm2. Jc shows a familiar linear dependence on P × t in logarithmic scales. We calculate the energy levels of the phase- and flux-type qubits using the achievable junction parameters and show that the fabricated Nb/Al-AlOx/Nb tunnel junctions can be used conveniently for quantum computation applications in the future.
Received: 15 January 2009
Revised: 06 March 2009
Accepted manuscript online:
Fund: Project supported by the National
Natural Science Foundation of China (Grant Nos 10534060 and
10874231) and the Ministry of Science and Technology of China (Grant
Nos 2006CB601007, 2006CB921107, and 2009CB929102).
Cite this article:
Cao Wen-Hui(曹文会), Yu Hai-Feng(于海峰), Tian Ye (田野), Yu Hong-Wei(于洪伟),Ren Yu-Feng (任育峰), Chen Geng-Hua (陈赓华),andZhao Shi-Ping (赵士平) Nb/Al-AlOx/Nb junctions with controllable critical current density for qubit application 2009 Chin. Phys. B 18 5044
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