title: Batchwise growth of silica cone patterns via self-assembly of aligned nanowires.
abstract: Silica-cone patterns self-assembled from well-aligned nanowires are synthesized using gallium droplets as the catalyst and silicon wafers as the silicon source. The cones form a triangular pattern array radially on almost the whole surface of the molten Ga ball. Detailed field-emission scanning electron microscopy (SEM) analysis shows that the cone-pattern pieces frequently slide off and are detached from the molten Ga ball surface, which leads to the exposure of the catalyst surface and the growth of a new batch of silicon oxide nanowires as well as the cone patterns. The processes of growth and detachment alternate, giving rise to the formation of a volcano-like or a flower-like structure with bulk-quantity pieces of cone patterns piled up around the Ga ball. Consequently, the cone-patterned layer grows batch by batch until the reaction is terminated. Different to the conventional metal-catalyzed growth model, the batch-by-batch growth of the triangular cone patterns proceeds on the molten Ga balls via alternate growth on and detachment from the catalyst surface of the patterns; the Ga droplet can be used continuously and circularly as an effective catalyst for the growth of amorphous SiO(x) nanowires during the whole growth period. The intriguing batchwise growth phenomena may enrich our understanding of the vapour-liquid-solid (VLS) growth mechanism for the catalyst growth of nanowires or other nanostructures and may offer a different way of self-assembling novel silica nanostructures.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, PR China.
authors.forename: Shudong
authors.initials: S
authors.lastname: Luo
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhou
authors.forename: Weiguo
authors.initials: W
authors.lastname: Chu
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.forename: Zengxing
authors.initials: Z
authors.lastname: Zhang
authors.forename: Lifeng
authors.initials: L
authors.lastname: Liu
authors.forename: Dongfang
authors.initials: D
authors.lastname: Liu
authors.forename: Yanjuan
authors.initials: Y
authors.lastname: Xiang
authors.forename: Wenjun
authors.initials: W
authors.lastname: Ma
authors.forename: Sishen
authors.initials: S
authors.lastname: Xie
mesh_terms: D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D012822:Silicon Dioxide