Method for making a single-step etch mask for 3D monolithic nanostructures.

Current nanostructure fabrication by etching is usually limited to planar structures as they are defined by a planar mask. The realization of three-dimensional (3D) nanostructures by etching requires technologies beyond planar masks. We present a method for fabricating a 3D mask that allows one to etch three-dimensional monolithic nanostructures using only CMOS-compatible processes.

Observation of sub-Bragg diffraction of waves in crystals.

We investigate the diffraction conditions and associated formation of stop gaps for waves in crystals with different Bravais lattices. We identify a prominent stop gap in high-symmetry directions that occurs at a frequency below the ubiquitous first-order Bragg condition. This sub-Bragg-diffraction condition is demonstrated by reflectance spectroscopy on two-dimensional photonic crystals with a centered rectangular lattice, revealing prominent diffraction peaks for both the sub-Bragg and first-order Bragg conditions.

Method to deterministically study photonic nanostructures in different experimental instruments.

We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the nanostructure is made during the fabrication of the structure. These maps are made using a series of micrographs with successively decreasing magnifications.

Periodic arrays of deep nanopores made in silicon with reactive ion etching and deep UV lithography.

We report on the fabrication of periodic arrays of deep nanopores with high aspect ratios in crystalline silicon. The radii and pitches of the pores were defined in a chromium mask by means of deep UV scan and step technology. The pores were etched with a reactive ion etching process with SF(6), optimized for the formation of deep nanopores.

Highly selective optical-sensing membranes, containing calix[4]arene chromoionophores, for Pb2+ ions.

Plasticized poly(vinyl chloride) (PVC) optode membranes containing novel calix[4]arene chromoionophores 1 or 2 and one equivalent of a lipophilic anion respond to Pb2+ ions with high selectivity over alkali, alkaline-earth, and other heavy metal ions. This selectivity stems from the combination of ligand specificity and a unique ion exchange scheme that employs both monovalent metal ions and protons as the exchanged ions. Complexation of Pb2+ ions inside the membrane is accompanied by deprotonation of the chromoionophores, which causes a bathochromic shift of the absorption maximum lambda(max).