Angle-independent structural colors of silicon

Abstract

Abstract. Structural colors are optical phenomena of physical origin, where microscale and nanoscale structures determine the reflected spectrum of light. Artificial structural colors have been realized within recent years. However, multilayer structures require substantial fabrication. Instead we considered one-layer surface textures of silicon. We explored four patterns of square structures in a square lattice with periods of 500, 400, 300, and 200 nm. The reflectivity and daylight-colors were measured and compared with simulations based on rigorously coupledwave analysis with excellent agreement. Based on the 200-nm periodic pattern, it was found that angle-independent specular colors up to 60 deg of incidence may be provided. The underlying mechanisms include (1) the suppression of diffraction and (2) a strong coupling of light to localized surface states. The strong coupling yields absorption anomalies in the visual spectrum, causing robust colors to be defined for a large angular interval. The result is a manifestation of a uniformly defined color, similar to pigment-based colors. These mechanisms hold potential for color engineering and can be used to explain and predict the structural-color appearance of silicon-based textures for a wide range of structural parameters.

Plasmonic Colors: Toward Mass Production of Metasurfaces

“…In contrast to the blue 200 nm period pattern, the color response of the 300 nm period pattern varies strongly with the orientation of the sample with respect to the light source and camera. This dependence is well described in literature and illustrates the requirement, due to the frequency range of the human visible spectrum, for nanoscale patterns with periodicities on the order of 200 nm or smaller.…”

Focused Ion Beam Direct Fabrication of Subwavelength Nanostructures on Silicon for Multicolor Generation

“…This forms a basis for the single‐step fabrication approach of color filters by FIB. The developed approach is fast due to single‐step involved compared to multistep lithography‐based approaches and thermal dewetting methods based on FIB templating reported previously . The diameter “ D ” and the period “ P ” of subwavelength nanoholes are controlled via FIB parameters for light manipulation over the visible spectrum and tuning of the structural color generated (more experimental details in Figures S2 and S3 in the Supporting Information).…”

“…A wide range of high index color filters in Si have been demonstrated by polarization sensitive designs of nanowires (NW), nanodisks (ND), nanoparticles (NP), and nanoholes (NH) through light scattering from individual NW/ND/NP/NH . These designs have been shown to exhibit a wavelength selective coupling of visible light with its guiding modes and rendering a specific color.…”

Manipulating the Orientations of the Electric and Magnetic Dipoles Induced in Silicon Nanoparticles for Multicolor Display

“…Color display based on regularly arranged silicon (Si), germanium (Ge) and titanium dioxide (TiO 2 ) nanopillars (NPs) has been successfully demonstrated. For Si‐based arrays, a thin film of amorphous Si deposited on a silica substrate was used to fabricate Si NPs .…”