title: Complex chiral colloids and surfaces via high-index off-cut silicon.
abstract: Silicon wafers are commonly etched in potassium hydroxide solutions to form highly symmetric surface structures. These arise when slow-etching {111} atomic planes are exposed on standard low-index surfaces. However, the ability of nonstandard high-index wafers to provide more complex structures by tilting the {111} planes has not been fully appreciated. We demonstrate the power of this approach by creating chiral surface structures and nanoparticles of a specific handedness from gold. When the nanoparticles are dispersed in liquids, gold colloids exhibiting record molar circular dichroism (>5 × 10(9) M(-1) cm(-1)) at red wavelengths are obtained. The nanoparticles also present chiral pockets for binding.
authors.affiliation: Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: McPeak
authors.forename: Christian D
authors.initials: CD
authors.lastname: van Engers
authors.forename: Mark
authors.initials: M
authors.lastname: Blome
authors.forename: Jong Hyuk
authors.initials: JH
authors.lastname: Park
authors.forename: Sven
authors.initials: S
authors.lastname: Burger
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Gosálvez
authors.forename: Ava
authors.initials: A
authors.lastname: Faridi
authors.forename: Yasmina R
authors.initials: YR
authors.lastname: Ries
authors.forename: Ayaskanta
authors.initials: A
authors.lastname: Sahu
authors.forename: David J
authors.initials: DJ
authors.lastname: Norris