Chemical stabilization of porous silicon for enhanced biofunctionalization with immunoglobulin.

Porous silicon (PSi) is widely used in biological experiments, owing to its biocompatibility and well-established fabrication methods that allow tailoring its surface. Nevertheless, there are some unresolved issues such as deciding whether the stabilization of PSi is necessary for its biological applications and evaluating the effects of PSi stabilization on the surface biofunctionalization with proteins. In this work we demonstrate that non-stabilized PSi is prone to detachment owing to the stress induced upon biomolecular adsorption.

Highly flexible method for the fabrication of photonic crystal slabs based on the selective formation of porous silicon.

A novel fabrication method of Si photonic slabs based on the selective formation of porous silicon is reported. Free-standing square lattices of cylindrical air holes embedded in a Si matrix can be achieved by proton beam irradiation followed by electrochemical etching of Si wafers. The photonic band structures of these slabs show several gaps for the two symmetry directions for reflection through the z-plane.

Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method.

A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach.

Mass fabrication technique for polymeric replicas of arrays of insect corneas.

Motivated to develop a technique for producing many high-fidelity replicas for the sacrifice of a single biotemplate, we combined a modified version of the conformal-evaporated-film-by-rotation technique and electroforming to produce a master negative made of nickel from a composite biotemplate comprising several corneas of common blowflies. This master negative can function as either a mold for casting multiple replicas or a die for stamping multiple replicas. An approximately 250 nm thick nickel film was thermally deposited on an array of blowfly corneas to capture the surface features with high fidelity and then a roughly 60 microm thick structural layer of nickel was electroformed onto the thin layer to give it the structural integrity needed for casting or stamping.