Scalable, Tunable Josephson Junctions and DC SQUIDs Based on CVD Graphene
Scalable, Tunable Josephson Junctions and DC SQUIDs Based on CVD Graphene
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DOI：
10.1109/tasc.2019.2897999
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发表时间：
2019-02
影响因子：
1.8
通讯作者：
Tianyi Li;J. Gallop;L. Hao;E. Romans
中科院分区：
文献类型：
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作者：
Tianyi Li;J. Gallop;L. Hao;E. Romans
由于石墨烯的载流子密度和电阻率在很大程度上取决于费米能级，以石墨烯为弱连接的约瑟夫森结可以通过栅极电压容易地调节其I-V特性。以前关于超导体-石墨烯-超导体（SGS）结和超导量子干涉器件（SQUID）的大多数工作都是基于机械剥离的石墨烯，这与大规模生产不兼容。在这里，我们表明，SGS结和直流SQUID可以很容易地从化学气相沉积（CVD）石墨烯制造，并表现出良好的电子性能。SGS结可以工作，没有任何滞后，在其电特性从1.5 K下降到320 mK的基础温度，和临界电流可以有效地调谐的栅极电压高达一个数量级。因此，由这些结组成的直流SQUID可以通过磁场和栅极电压调节其临界电流。
Since the carrier density and resistivity of graphene are heavily dependent on the Fermi level, Josephson junctions with graphene as the weak link can have their I–V properties easily tuned by the gate voltage. Most of the previous work on superconductor–graphene–superconductor (SGS) junctions and superconducting quantum interference devices (SQUIDs) were based on mechanically exfoliated graphene, which is not compatible with large scale production. Here, we show that SGS junctions and dc SQUIDs can be easily fabricated from chemical vapor deposition (CVD) graphene and exhibit good electronic properties. The SGS junctions can work without any hysteresis in their electrical characteristics from 1.5 K down to a base temperature of 320 mK, and the critical current can be effectively tuned by the gate voltage by up to an order of magnitude. As a result, dc SQUIDs made up of these junctions can have their critical current tuned by both the magnetic field and the gate voltage.