Sestoft Joachim E, Marnauza Mikelis, Olsteins Dags, Kanne Thomas, Schlosser Rasmus D, Chen I-Ju, Grove-Rasmussen Kasper, Nygård Jesper
Center for Quantum Devices and Nano-science Center, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
Nano Lett. 2024 Jul 10;24(27):8394-8401. doi: 10.1021/acs.nanolett.4c02055. Epub 2024 Jun 12.
Hybrid semiconductor-superconductor nanowires have emerged as a cornerstone in modern quantum devices. Integrating such nanowires into hybrid devices typically requires extensive postgrowth processing which may affect device performance unfavorably. Here, we present a technique for in situ shadowing superconductors on nanowires and compare the structural and electronic properties of Al junctions formed by shadowing versus etching. Based on transmission electron microscopy, we find that typical etching procedures lead to atomic-scale surface roughening. This surface perturbation may cause a reduction of the electron mobility as demonstrated in transport measurements. Further, we display advanced shadowing geometries aiding in the pursuit of bringing fabrication of hybrid devices in situ. Finally, we give examples of shadowed junctions exploited in various device geometries that exhibit high-quality quantum transport signatures.
混合半导体 - 超导体纳米线已成为现代量子器件的基石。将此类纳米线集成到混合器件中通常需要大量的生长后处理，这可能会对器件性能产生不利影响。在此，我们展示了一种在纳米线上原位遮蔽超导体的技术，并比较了通过遮蔽与蚀刻形成的铝结的结构和电子特性。基于透射电子显微镜，我们发现典型的蚀刻工艺会导致原子尺度的表面粗糙度增加。这种表面扰动可能会导致电子迁移率降低，这在输运测量中得到了证实。此外，我们展示了先进的遮蔽几何结构，有助于实现混合器件的原位制造。最后，我们给出了在各种器件几何结构中使用的遮蔽结的示例，这些结展现出高质量的量子输运特征。
