Fabrication and Field-Emission Properties of Vertically-Aligned Tapered [110]Si Nanowire Arrays Prepared by Nanosphere Lithography and Electroless Ag-Catalyzed Etching

Feng, Ziyan; Lin, Kuo-Min; Chen, Y. C.; Cheng, Sheng-Tzong

doi:10.1142/s1793292018501084

Cited by 2 publications

(1 citation statement)

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“…In the case of high-AR structures, capillary forces might have a detrimental effect on the device performance due to the bending or deflection of the supporting wires. One way to obtain sharper nanowires is to adapt the vertical SiNW shape toward a more tapered or conical form by either a top-down or bottom-up fabrication process using anisotropic etching or epitaxial growth techniques, respectively [5][6][7][8][9][10][11]. These tapered silicon nanocones (SiNCs) can be used for a multitude of applications, ranging from photovoltaics to nanofluidics, nanophotonics, and nanoelectronic applications [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Large Dense Periodic Arrays of Vertically Aligned Sharp Silicon Nanocones

et al. 2022

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Convex cylindrical silicon nanostructures, also referred to as silicon nanocones, find their value in many applications ranging from photovoltaics to nanofluidics, nanophotonics, and nanoelectronic applications. To fabricate silicon nanocones, both bottom-up and top-down methods can be used. The top-down method presented in this work relies on pre-shaping of silicon nanowires by ion beam etching followed by self-limited thermal oxidation. The combination of pre-shaping and oxidation obtains high-density, high aspect ratio, periodic, and vertically aligned sharp single-crystalline silicon nanocones at the wafer-scale. The homogeneity of the presented nanocones is unprecedented and may give rise to applications where numerical modeling and experiments are combined without assumptions about morphology of the nanocone. The silicon nanocones are organized in a square periodic lattice, with 250 nm pitch giving arrays containing 1.6 billion structures per square centimeter. The nanocone arrays were several mm2 in size and located centimeters apart across a 100-mm-diameter single-crystalline silicon (100) substrate. For single nanocones, tip radii of curvature < 3 nm were measured. The silicon nanocones were vertically aligned, baring a height variation of < 5 nm (< 1%) for seven adjacent nanocones, whereas the height inhomogeneity is < 80 nm (< 16%) across the full wafer scale. The height inhomogeneity can be explained by inhomogeneity present in the radii of the initial columnar polymer mask. The presented method might also be applicable to silicon micro- and nanowires derived through other top-down or bottom-up methods because of the combination of ion beam etching pre-shaping and thermal oxidation sharpening. Graphic abstract A novel method is presented where argon ion beam etching and thermal oxidation sharpening are combined to tailor a high-density single-crystalline silicon nanowire array into a vertically aligned single-crystalline silicon nanocones array with < 3 nm apex radius of curvature tips, at the wafer scale.

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