Solid-state reactions at niobium–germanium interfaces in hybrid quantum electronics

IF 1.4 4区物理与天体物理 Q4 MATERIALS SCIENCE, MULTIDISCIPLINARY

AIP Advances Pub Date : 2024-09-13 DOI:10.1063/5.0221366

B. Langa, D. Sapkota, I. Lainez, R. Haight, B. Srijanto, L. Feldman, H. Hijazi, X. Zhu, L. Hu, M. Kim, K. Sardashti

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Abstract

Hybrid superconductor–semiconductor materials systems are promising candidates for quantum computing applications. Their integration into superconducting electronics has enabled on-demand voltage tunability at millikelvin temperatures. Ge quantum wells have been among the semiconducting platforms interfaced with superconducting Al to realize voltage tunable Josephson junctions. Here, we explore Nb as a superconducting material in direct contact with Ge channels by focusing on the solid-state reactions at the Nb/Ge interfaces. We employ Nb evaporation at cryogenic temperatures (∼100 K) to establish a baseline structure with atomically and chemically abrupt Nb/Ge interfaces. By conducting systematic photoelectron spectroscopy and transport measurements on Nb/Ge samples across varying annealing temperatures, we elucidated the influence of Ge out-diffusion on the ultimate performance of superconducting electronics. This study underlines the need for low-temperature growth to minimize chemical intermixing and band bending at the Nb/Ge interfaces.

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混合量子电子学中铌锗界面的固态反应

混合超导体-半导体材料系统是量子计算应用的理想候选材料。将它们集成到超导电子器件中，可以在毫开尔文温度下实现按需电压可调。Ge 量子阱是与超导 Al 相连接的半导体平台之一，可实现电压可调的约瑟夫森结。在这里，我们通过重点研究铌/锗界面的固态反应，探索铌作为超导材料与 Ge 沟道的直接接触。我们采用在低温（∼100 K）下蒸发铌的方法，建立了具有原子和化学突变铌/锗界面的基线结构。通过对不同退火温度下的 Nb/Ge 样品进行系统的光电子能谱和传输测量，我们阐明了 Ge 外扩散对超导电子器件最终性能的影响。这项研究强调了低温生长的必要性，以尽量减少铌/锗界面上的化学混杂和带弯曲。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

AIP Advances NANOSCIENCE & NANOTECHNOLOGY-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

2.80

自引率

6.20%

发文量

1233

审稿时长

2-4 weeks

期刊介绍： AIP Advances is an open access journal publishing in all areas of physical sciences—applied, theoretical, and experimental. All published articles are freely available to read, download, and share. The journal prides itself on the belief that all good science is important and relevant. Our inclusive scope and publication standards make it an essential outlet for scientists in the physical sciences. AIP Advances is a community-based journal, with a fast production cycle. The quick publication process and open-access model allows us to quickly distribute new scientific concepts. Our Editors, assisted by peer review, determine whether a manuscript is technically correct and original. After publication, the readership evaluates whether a manuscript is timely, relevant, or significant.