Nanostripe-Confined Catalyst Formation for Uniform Growth of Ultrathin Silicon Nanowires

Uniform growth of ultrathin silicon nanowire (SiNW) channels is the key to accomplishing reliable integration of various SiNW-based electronics, but remains a formidable challenge for catalytic synthesis, largely due to the lack of uniform size control of the leading metallic droplets. In this work, we explored a nanostripe-confined approach to produce highly uniform indium (In) catalyst droplets that enabled the uniform growth of an orderly SiNW array via an in-plane solid–liquid–solid (IPSLS) guided growth directed by simple step edges. It was found that the size dispersion of the In droplets could be reduced substantially from ${\mathrm{D}}_{\mathrm{cat}}^{pl}$ = 20 ± 96 nm on a planar surface to only ${\mathrm{D}}_{\mathrm{cat}}^{ns}$ = 88 ± 13 nm when the width of the In nanostripe was narrowed to ${\mathrm{W}}_{\mathrm{str}}=$ 100 nm, which could be qualitatively explained in a confined diffusion and nucleation model. The improved droplet uniformity was then translated into a more uniform growth of ultrathin SiNWs, with diameter of only ${\mathrm{D}}_{\mathrm{nw}}=$ 28 ± 4 nm, which has not been reported for single-edge guided IPSLS growth. These results lay a solid basis for the construction of advanced SiNW-derived field-effect transistors, sensors and display applications.