Growth of curved single-crystal silicon nanostructures via laser-induced localized thermal gradient steering

Lattice anisotropy fundamentally dictates the spatial symmetry and rectilinear features of one-dimensional single-crystal nanostructures and defines the inherent scope of their morphological variety. This study presents a strategy leveraging scanning laser-induced cyclohexasilane liquid-phase chemical deposition to enable the continuous modulation of silicon nanostructure curvature alongside a strictly single-crystal epitaxial structure. We attribute the bending to the deflection of the high-gradient photothermal field generated by the focused laser, which functions as a dynamic and spatially asymmetric regulator. The localized thermal environment provides a potent kinetic driving force within the sub-micrometer reaction zone, steering the epitaxial stacking of silicon atoms along artificially defined spatiotemporal trajectories. This mechanism enables the simultaneous realization of curved morphologies and highly ordered crystal structures, effectively decoupling structural evolution from the geometric constraints typically associated with conventional growth processes. Additionally, leveraging the inherent advantages of the liquid-phase environment, n-type (phosphorus-doped) horizontal single-crystal silicon nanowires were grown, achieving an active carrier concentration of 4 × 10²⁰ atom per cm³ and a resistivity as low as 6.0 × 10^-4 Ω cm. The findings confirm the feasibility of modulating the growth trajectory of single-crystal silicon via localized kinetic control, which provides the theoretical and technical basis for the additive manufacturing of complex three-dimensional single-crystal silicon nanostructures.