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 Si0.75Ge0.25/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 cm2/(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.

Paper link: https://pubs.acs.org/doi/10.1021/acs.nanolett.5c02477