Fabrication of diffraction gratings by top-down and bottom-up approaches based on scanning probe lithography

Abstract

Generation of diffraction gratings by top-down and bottom-up approaches based on scanning probe lithography is demonstrated. With regard to top-down fabrication, silicon nanostructured diffraction gratings are fabricated through one-dimensional (1D) dip-pen-nanolithography (DPN). Nanodot arrays (two-dimensional simple cubic lattice) of alkanethiol self-assembled monolayers (SAMs) are printed by 1D DPN on an Au-film-coated silicon substrate with lattice distances of 700, 1000, and 1200 nm. Silicon nanocircular pillars of length hundreds of nanometers are generated by sequential Au etching and reactive ion etching (RIE) of the 1D DPN printed sample. The performance of the silicon diffraction gratings as a microspectrometer is demonstrated through red, green, and blue color diffraction with white light incident at 45°. Moreover, arrays of zirconia nanoparticles (NPs) with an average diameter of visible wavelength (ϕ ≈ 470 nm) on an Au substrate are generated via bottom-up fabrication of the diffraction gratings. Microarrays of hydrophilic alkanethiol SAMs are obtained by polymer pen lithography (PPL). Self-assembly of zirconia NPs occurs after the passivation of hydrophobic alkanethiol SAMs of the PPL-printed sample. Fraunhofer diffraction with a square aperture is observed for the zirconia NP diffraction grating fabricated by the bottom-up approach.