We demonstrate a maskless photochemical etching method that is capable of performing one-step etching of multi-level structures. This method uses a digital projector to focus an image onto the sample and define the etching pattern. By combining digital projection photochemical etching with diffraction phase microscopy, etch heights can be measured in situ in a non-destructive manner. This metho...

Periodic high aspect ratio GaAs nanopillars with widths in the range of 500-1000 nm are produced by metal-assisted chemical etching (MacEtch) using n-type (100) GaAs substrates and Au catalyst films patterned with soft lithography. Depending on the etchant concentration and etching temperature, GaAs nanowires with either vertical or undulating sidewalls are formed with an etch rate of 1-2 μm/mi...

The in vitro dentin permeability of the constituents of two types of conventional phosphoric acid etching agents which had different viscosities, and their pH changes after being permeated dentin were investigated. It was recognized that, even though the etching was for a short time (one minute) followed by rinsing, the etching agents were still detected in the dentinal tubules which had permea...

We report on the fabrication of quantum photonic integrated circuits based on suspended GaAs membranes. The fabrication process consists of a single lithographic step followed by inductively coupled-plasma dry etching through an electron-beam-resist mask and wet etching of a sacrificial layer. This method does not require depositing, etching, and stripping a hard mask, greatly reducing fabricat...

We demonstrate GaAs pillar array-based light emitting diodes (LEDs) with axial p-in junctions fabricated using a room-temperature metal-assisted chemical etching (MacEtch) method. Variations in vertical etch rates for all three doping types of GaAs are investigated as a function of etching temperature, oxidant/acid concentration ratio, and dilution of the etching solution. Control over nanopill...

The main objective of this research is to develop a micro and nanogap structure using dry anisotropic etching –Reactive Ion EtchingRIE. Amorphous silicon material is used in the micro and nanogap structure and gold as electrode. The fabrication processes of the micro and nanostructure are based on conventional photolithography, wet etching for the Al pattern and wet etching for a-Si pattern usi...

PURPOSE The goal of this in vitro study was to identify the topographical features of the enamel surface deproteinized and etched with phosphoric acid (H3PO4) compared to phosphoric acid alone. MATERIALS AND METHOD Ten extracted lower first and second permanent molars were polished with pumice and water, and then divided into 4 equal buccal sections having similar physical and chemical proper...

BACKGROUND Based on contradictory findings concerning the use of lasers for enamel etching, the purpose of this study was to investigate the shear bond strength of teeth prepared for bonding with Er-YAG laser etching and compare them with phosphoric acid etching. MATERIALS AND METHODS In this in vitro study forty - eight premolars, extracted for orthodontic purposes were randomly divided in t...

Many potential applications of porous silicon nanowires (SiNWs) fabricated with metal-assisted chemical etching are highly dependent on the precise control of morphology for device optimization. However, the effects of key etching parameters, such as the amount of deposited metal catalyst, HF-oxidant molar ratio (χ), and solvent concentration, on the morphology and etching kinetics of the SiNWs...

Introduction: Due to concerns about histological caries and recurrent caries after the use of sealants, adhesive systems containing fluoride and antibacterial agents have been proposed. The aim of this study was to evaluate the microleakage of sealants after the use of antibacterial chlorhexidine solution on etched enamel with and without the use of fifth- and sixth-generation adhesive systems....