Tuning Supercurrent in Josephson Field-Effect Transistors Using h-BN Dielectric
Tuning Supercurrent in Josephson Field-Effect Transistors Using h-BN Dielectric
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DOI：
10.1021/acs.nanolett.0c03183
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发表时间：
2021-02-22
期刊：
影响因子：
10.8
通讯作者：
Shabani, Javad
中科院分区：
文献类型：
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作者：
Barati, Fatemeh;Thompson, Josh P.;Shabani, Javad
外延Al-InAs异质结是探索介观和拓扑超导电性的一个很有前途的材料平台。在这些异质结上制作的约瑟夫森结场效应晶体管(JJ-FET)的一个独特特性是能够利用金属栅调谐超电流。在这里，我们报道了栅极可调谐Al-InAs JJ-FET的制作和测量，其中与InAs接触的栅电介质是通过机械剥离的六方氮化硼(h-BN)然后干式转移产生的。我们讨论了一种通用的制备工艺，它实现了层状材料转移和Al-InAs异质结之间的兼容性，使我们只使用5 nm厚的h-BN片就可以实现超流的完全栅极可调。我们的研究表明，外延约瑟夫森结的原始性质，如正常电阻和临界电流的乘积，IcRn，保持不变。此外，互补测量证实，与原子层沉积Al_2O_3相比，使用h-BN介质对沟道密度的改变较小。
Epitaxial Al-InAs heterostructures appear as a promising materials platform for exploring mesoscopic and topological superconductivity. A unique property of Josephson junction field effect transistors (JJ-FETs) fabricated on these heterostructures is the ability to tune the supercurrent using a metallic gate. Here, we report the fabrication and measurement of gate-tunable Al-InAs JJ-FETs in which the gate dielectric in contact with the InAs is produced by mechanically exfoliated hexagonal boron nitride (h-BN) followed by dry transfer. We discuss a versatile fabrication process that enables compatibility between layered material transfer and Al-InAs heterostructures that allows us to achieve full gate-tunability of supercurrent by using only 5 nm thick h-BN flakes. Our study shows that pristine properties of epitaxial Josephson junctions, such as product of normal resistance and critical current, IcRn, are preserved. Furthermore, complementary measurements confirm that using h-BN dielectric changes the channel density less when compared to atomic layer deposition of Al2O3.