biostudies-literatureUnknown12(7)An JPrecise control over quantum dot (QD) position and size is critical for quantum electronics but typically requires complex nanofabrication. Here, we report a step-confined heteroprecursor supply (sc-HPS) strategy for growth of crystalline germanium (c-Ge) QDs at predefined step edges within planar ultrathin silicon nanowire (SiNW) channels, eliminating the need for high-resolution lithography. Unlike conventional in-plane solid-liquid-solid growth using a uniform amorphous silicon precursor, sc-HPS uses a spatially confined amorphous germanium (a-Ge) layer defined by oblique patterning of a SiO₂/a-Ge stack. This restricts Ge supply to a narrow strip along the step edge, enabling nucleation and tunable QD diameters of ~25 to 150 nm, sandwiched between two epitaxially connected SiScience advanceseaed0335https://www.ebi.ac.uk/biostudies/studies/S-EPMC12904181biostudies-literatureLithography-free, site-controlled germanium quantum dots in silicon nanowires for single-hole transistors operating up to 50 K.PMC12904181Yu LZhao LLi SHu ZHe ZAn JSong XWang JfalseLithography-free, site-controlled germanium quantum dots in silicon nanowires for single-hole transistors operating up to 50 K.Precise control over quantum dot (QD) position and size is critical for quantum electronics but typically requires complex nanofabrication. Here, we report a step-confined heteroprecursor supply (sc-HPS) strategy for growth of crystalline germanium (c-Ge) QDs at predefined step edges within planar ultrathin silicon nanowire (SiNW) channels, eliminating the need for high-resolution lithography. Unlike conventional in-plane solid-liquid-solid growth using a uniform amorphous silicon precursor, sc-HPS uses a spatially confined amorphous germanium (a-Ge) layer defined by oblique patterning of a SiO₂/a-Ge stack. This restricts Ge supply to a narrow strip along the step edge, enabling nucleation and tunable QD diameters of ~25 to 150 nm, sandwiched between two epitaxially connected Si2026-01-01T00:00:00Z2026 Feb2026-07-15T16:39:46.363Z2026-07-07T03:08:36.492ZS-EPMC129041814168690110.1126/sciadv.aed0335