title: Optical absorption characteristic of highly ordered and dense two-dimensional array of silicon nanodiscs.
abstract: We created a two-dimensional array of sub-10 nm Si-nanodiscs (Si-NDs), i.e. a 2D array of Si-NDs, with a highly ordered arrangement and dense NDs by using a new top-down technique comprising advanced damage-free neutral-beam (NB) etching and a bio-template (iron oxide core) as a uniform sub-10 nm etching mask. The bandgap energy (E(g)) of the fabricated 2D array of Si-NDs can be simply controlled from 2.2 to 1.3 eV by changing the ND thickness from 2 to 12 nm. Due to weak quantum confinement existing in the diameter direction resulting from the sub-10 nm Si-ND diameter, even though the thickness of the Si-ND is much larger than the Bohr radius of Si, E(g) is still larger than the 1.1 eV E(g) of bulk Si. Si-ND not only has wide controllable E(g) but also a high absorption coefficient due to quantum confinement in three dimensions. This new technique is a promising candidate for developing new nanostructures and could be integrated into the fabrication of nanoelectronic devices.
authors.affiliation: Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
authors.forename: Chi-Hsien
authors.initials: CH
authors.lastname: Huang
authors.forename: Xuan-Yu
authors.initials: XY
authors.lastname: Wang
authors.forename: Makoto
authors.initials: M
authors.lastname: Igarashi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Murayama
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Okada
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamashita
authors.forename: Seiji
authors.initials: S
authors.lastname: Samukawa