Scalable and Tunable In-Plane Ge/Si(001) Nanowires Grown by Molecular Beam Epitaxy.

Wang, Jian-Huan; Ming, Ming; Huang, Ding-Ming; Zhang, Jie-Yin; Luo, Yi; Fu, Bin-Xiao; Chu, Yi-Xin; Yao, Yuan et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Germanium nanostructures offer significant potential in developing advanced integrated circuits and disruptive quantum technologies, yet achieving both scalability and high carrier mobility remains a challenge in materials science. Here, we report an original low-temperature epitaxial method for the growth of site-controlled in-plane germanium nanowires with high hole mobility by molecular beam epitaxy. By reducing the growth temperature, we effectively suppress Si-Ge interdiffusion, ensuring pure germanium composition within the nanowires while preserving their high crystalline quality. The method employs prepatterned ridges on strain-relaxed Si<sub>0.75</sub>Ge<sub>0.25</sub>/Si(001) substrates as tailored templates, enabling control over the position, length, spacing, and cross-sectional shape of the nanowires. Electrical measurements of field-effect devices made from as-grown germanium nanowires show that the nanowires are of hole conduction with mobility exceeding 7000 cm<sup>2</sup>/(V s) at 2-20 K. The method paves a way for fabrication of scalable germanium nanowire networks, providing a reliable platform for the developments of high-performance nanoelectronics and multiqubit chips.