A highly chemical reactive ion etching process has been developed for MOVPE-grown GaN on sapphire. The key element for the enhancement of the chemical property during etching is the use of a fluorine containing gas in a chlorine based chemistry. In the perspective of using GaN substrates for homo-epitaxy of high quality GaN/AlGaN structures we have used the above described RIE process to smooth...

With the help of a nanoscale trench, the composition and conductance distributions of single GeSi quantum dots (QDs) are obtained by conductive atomic force microscopy combined with selective chemical etching. However, the obtained composition and current distributions are unwonted and inconsistent on the QDs grown at 680 °C. With a series of confirmatory experiments, it is suggested that a thi...

We report a simple, clean, and highly anisotropic hydrogen etching method for chemical vapor deposited (CVD) graphene catalyzed by the copper substrate. By exposing CVD graphene on copper foil to hydrogen flow around 800 °C, we observed that the initially continuous graphene can be etched to have many hexagonal openings. In addition, we found that the etching is temperature dependent. Compared ...

The techniques commonly used for observing the deformation mechanisms underneath a Vickers indentation in metallic glasses (chemical etching, bonded interface) induce artefacts such as cracks or semi-circular shear-bands. We propose an alternative technique based on the propagation of indentation corner cracks through a pre-existing imprint, which is possible in metallic glasses such as iron-ba...

In the current study, monocrystalline silicon nanowire arrays (SiNWs) were prepared through a metal-assisted chemical etching method of silicon wafers in an etching solution composed of HF and H2O2. Photoelectric properties of the monocrystalline SiNWs are improved greatly with the formation of the nanostructure on the silicon wafers. By controlling the hydrogen peroxide concentration in the et...

Coupling of fiber posts to composites is hampered by absence of chemical union between epoxy resins and methacrylate-based resins. This study examined a clinically feasible protocol for creating micromechanical retention on the surface of fiber posts, using hydrogen peroxide etching to remove the surface layer of epoxy resin. This was followed by silanization of the exposed quartz fibers to enh...

OBJECTIVES To verify the influence of different etching procedures of the post-surface on microtensile bond strength values between fiber posts and composite core materials. METHODS 60 DT Light Posts were divided into 10 subgroups using five different chemical surface treatments and two composite materials to build-up the abutment. Chemical surface treatments including etching with potassium ...

Argon-ion etching and various other chemical etchants were applied to conventional and gold-containing dental alloys and amalgams. The polished and etched specimens were studied by optical and/or electron optical methods and by energy-dispersive x-ray spectroscopy. Chemical etchants, though effective, have the disadvantage of accentuating surface scratches. This, in turn, causes difficulty in t...

A microhole array in a common single-mode fiber is fabricated by selective chemical etching of femtosecond-laser-induced fiber Bragg grating (FBG), which has a laser-modified region extending from the fiber core to the cladding-air boundary due to laser self-focusing. The shape and size of the orderly microhole on the fiber surface are controlled via changing conditions of FBG fabrication and c...

Femtosecond laser irradiation followed by chemical etching (FLICE) with hydrogen fluoride (HF) is an emerging technique for the fabrication of directly buried, three-dimensional microfluidic channels in silica. The procedure, as described in literature, consists of irradiating a silica slab followed by chemical etching using hydrogen fluoride. With aqueous HF the etching process is diffusion-li...