Icking Eike, Emmerich David, Watanabe Kenji, Taniguchi Takashi, Beschoten Bernd, Lemme Max C, Knoch Joachim, Stampfer Christoph
JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany.
Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany.
Nano Lett. 2024 Sep 18;24(37):11454-11461. doi: 10.1021/acs.nanolett.4c02463. Epub 2024 Sep 4.
Cryogenic field-effect transistors (FETs) offer great potential for applications, the most notable example being classical control electronics for quantum information processors. For the latter, on-chip FETs with low power consumption are crucial. This requires operating voltages in the millivolt range, which are only achievable in devices with ultrasteep subthreshold slopes. However, in conventional cryogenic metal-oxide-semiconductor (MOS)FETs based on bulk material, the experimentally achieved inverse subthreshold slopes saturate around a few mV/dec due to disorder and charged defects at the MOS interface. FETs based on two-dimensional materials offer a promising alternative. Here, we show that FETs based on Bernal stacked bilayer graphene encapsulated in hexagonal boron nitride and graphite gates exhibit inverse subthreshold slopes of down to 250 μV/dec at 0.1 K, approaching the Boltzmann limit. This result indicates an effective suppression of band tailing in van der Waals heterostructures without bulk interfaces, leading to superior device performance at cryogenic temperature.
低温场效应晶体管（FET）在应用方面具有巨大潜力，最显著的例子是量子信息处理器的经典控制电子学。对于后者，低功耗的片上FET至关重要。这需要毫伏范围内的工作电压，而这只有在具有超陡亚阈值斜率的器件中才能实现。然而，在基于体材料的传统低温金属氧化物半导体（MOS）FET中，由于MOS界面处的无序和带电缺陷，实验测得的反向亚阈值斜率在几毫伏/十倍频程左右饱和。基于二维材料的FET提供了一种有前景的替代方案。在此，我们表明，基于封装在六方氮化硼和石墨栅极中的伯纳尔堆叠双层石墨烯的FET在0.1 K时表现出低至250 μV/十倍频程的反向亚阈值斜率，接近玻尔兹曼极限。这一结果表明在没有体界面的范德华异质结构中有效抑制了能带尾迹，从而在低温下实现了卓越的器件性能。
