Direct Transcription of Two‐Dimensional Colloidal Crystal Arrays into Three‐Dimensional Photonic Crystals

Abstract

A simple protocol for the fabrication of three-dimensional (3D) photonic crystals in silicon is presented. Surface structuring by nanosphere lithography is merged with a novel silicon etching method to fabricate ordered 3D architectures. The SPRIE method, sequential passivation reactive ion etching, is a one-step processing protocol relying on sequential passivation and reactive ion etching reactions using C 4 F 8 and SF 6 plasma chemistries. The diffusion of fresh reactants and etch product species inside the etched channels is found to play an important role affecting the structural uniformity of the designed structures and the etch rate drift is corrected by adjusting the reaction times. High quality photonic crystals are thus obtained by adding the third dimension to the two-dimensional (2D) colloidal crystal assemblies through SPRIE. Careful adjustments of both mask design and lateral etch extent balance allow the implementation of even more complex functionalities including photonic crystal slabs and precise defect engineering. 3D photonic crystal lattices exhibiting optical stop-bands in the infrared spectral region are demonstrated, proving the potential of SPRIE for fast, simple, and large-scale fabrication of photonic structures.

Design Considerations for Unconventional Electrochemical Energy Storage Architectures

“…Bulk or surface redox reactions taking place in battery or supercapacitor electrodes are accompanied by variation of the dielectric constant of the constituent material (as well as considerable volume and shape modification) and could induce important changes of the optical response. [ 484,[494][495][496][497] Photonic crystal structures could be designed to enhance the optical transmission and render 'transparent' materials that are otherwise opaque or could be used to implement other type of visual illusion effects like diffracted color change upon charge-discharge cycling. And all this supplemented by enhanced electrochemical performances due to hierarchical micro-, nano-, meso-porous electrode framework.…”

Spherical Nanoparticle Arrays with Tunable Nanogaps and Their Hydrophobicity Enhanced Rapid SERS Detection by Localized Concentration of Droplet Evaporation

“…Periodic micro/nanostructured arrays have attracted considerable interests in recent years because of their applications in wide fi elds, such as active substrates for surface-enhanced Raman scattering spectroscopy (SERS), [1][2][3][4][5][6] chemical and biological sensors, [7][8][9][10][11][12] solar cells, [13][14][15] photonic crystal, [16][17][18][19] self-cleaning surfaces, [20][21][22] photocatalytic materials, [ 23 ] microfl uidic devices nanogaps with sub-10 nm between two nearest neighboring nanostructured units can produce plasmonic coupling, resulting in the electromagnetic fi eld enhancement and forming a large quantity effi cient "hot spots" for ultrasensitive SERS substrates. [45][46][47] Therefore, tuning the nanogap value properly to enhance plasmonic coupling is more meaningful to SERS examination.…”

Graphene-coated holey metal films: Tunable molecular sensing by surface plasmon resonance

“…Briefly, polystyrene spheres (980 nm in diameter, Microparticles GmbH) were deposited on soda-lime glass plates via an interfacial selfassembly protocol. 27,28 Reactive ion etching using O 2 chemistry (Oxford Plasmalab, 100 W RF power, 100 sccm O 2 , 25 mTorr, 12 min) was used to reduce the size of the colloids to half the nominal diameter. Subsequently, 2 nm of Ti followed by 25 nm of Au were deposited using physical vapor deposition.…”