Anti-reflective surfaces: Cascading nano/microstructuring

Abstract

The creation of anti-reflective surfaces is reliant on the engineering of the surface textures and patterns to enable efficient trapping or transmission of light. Here we demonstrate anti-reflective layers composed of hierarchical nano/microscale features that are prepared on Si using a combination of wet and dry etching processes, and which are both scalable and affordable. The performance of the structured surfaces was tested through optical measurements of the reflectance, transmittance, and scattering spectra from the visible to mid-infrared wavelength regions, and the results were verified using numerical simulations to identify the performance of the textured anti-reflective layers. The anti-reflective properties of the layers were shown to be dramatically improved by the composite nanostructured surfaces over a broad spectral range, which thus provides a basis for the design rules that are essential for the progress towards effective anti-reflector fabrication. At normal incidence, the hierarchical surfaces achieve reflectances that are 10–80 times lower than that of conventional single-etch nano-microstructures. Portions of the absorbed, transmitted, scattered, and reflected light in the visible-IR spectrum are presented to illustrate the results.

Impact of Laser Wavelength on the Optical and Electronic Properties of Black Diamond

“…Absorptance values were obtained by the well‐known conservation of energy relationship: ρ + τ + α = 1, where ρ , τ , and α are the reflectance, transmittance, and absorptance, respectively, of the sample under test . Figure reports the absorptance spectra of the three TM black diamond films fabricated in this work by laser treatment at λ fs = 400 nm (solid curves) compared to those previously obtained at λ fs = 800 nm (dotted curves) .…”

Fabrication of Hollow Core-Shell Type Si/C Nanocomposites by a Simple Process

“…To overcome the above-mentioned drawbacks, replacement of the bulk Si with silicon nanoparticles (Si-NPs), silicon nanowires (Si-NWs), silicon thin films, and silicon with hollow nanospaces [6][7][8][9][10][11][12][13]. In these nanostructured Si materials, the large volume change and the low Li ion diffusivity are relaxed because the whole Si anodes are easily filled with Li ions [14].…”

Plasmonic Sensor: Towards Parts-per-Billion Level Sensitivity

“…They are often used for determining the absolute quantum efficiency of light absorption, luminescence, reflectance, and scattering. (15) They can also be used for augmenting NDIR gas cells to increase the optical path length and thereby to miniaturize the sensing system. (16) If the surface of the integrating sphere is covered with a scattering plasmonic material, enhancement of the SEIRA signal is expected as a result of multiple interaction events.…”