Fast Fabrication Method Research Articles

Optical waveguides structured with photoaligning polymers

We present a novel fast fabrication method for making optical waveguides by using a photoaligning and a liquid-crystal polymer. A difference in the refractive indices in the core and cladding regions is achieved by use of polarized UV light to align the polymer chains differently. A refractive-index difference of Deltan = 0.07 was achieved. The propagation loss in a channel waveguide is 4 dB/cm at a wavelength of 1.55 microm. The fabrication method has only a few processing steps and yields short fabrication times. The waveguide structures offer possibilities for generating devices with new applications related to the polarization of the guided light.

Fast fabrication of large-area nanopore arrays by FIB

Fabrication of nanopore arrays is of great importance in nanodevices manufacture and basic scientific research. Focused ion beam (FIB) and electron beam lithography (EBL) have been widely used for fabrication of nanostructures.However, it takes very long time to fabricate nanostructure patterns of large area. In this p aper we report a novel fast fabrication method for nanopore arrays of large area by FIB. Each pixel of predesigned BMP file is regarded as a fabrication dot. B y matching the pixel of the presigned BMP pattern with the required fabrication area, nanopore arrays of large area can be fabricated in a very short time.

Nanoscale features influence epithelial cell morphology and cytokine production

Available, easy and fast fabrication methods of nanostructured surfaces, and the knowledge that cells in vivo interacts with nanometer-sized structures/objects, led us to study the impact of nanotopography on cell morphology and cytokine production. Uroepithelial cells were seeded on three different substrate types: two with defined nanometer topographies and a flat control, all three having identical surface chemistry. The nanostructured substrates contained hemispherical pillars or step edges, the latter in the form of parallel grooves and ridges. Qualitative and quantitative analysis of cell morphology and cytokine production were studied. Both quantities were significantly different between cells cultured on hemispherically structured surfaces compared to flat control surfaces. Cells cultured on hemispherically structured surfaces showed a decrease in IL-6 and IL-8 production and were less spread, less round and more stellate (larger dispersion). Only cell morphology differed between cells cultured on grooved surfaces and flat control surfaces. These findings suggest that epithelial cell morphology and cytokine production are dependent on the underlying nanotopography.

MgB 2 double-sided thick films fabricated on various metals by electrophoresis method

The paper reports a remarkably simple method for fast fabrication of double-sided MgB 2 thick films by electrophoresing precursor boron powders on various metallic substrates followed by an ex situ annealing in magnesium vapor. Both sides of the films are homogeneous in thickness and composition, and no significant difference in T c and J c is found between the MgB 2 thick films on both sides of metals. Scanning electron microscopy on both sides of the double-sided films show dense and homogeneous structure consisting of MgB 2 grains below 1 μm. The X-ray diffraction and resistance measurement of the MgB 2 thick films on different metals show that the films are random oriented and have the onset superconducting temperature T c in the range of about 32–38 K. Estimates using hysteresis loops and Bean model give the critical current densities of the thick films are above 10 5 A/cm 2 in zero field and 5 K. The irreversibility fields of the thick films are comparable to those obtained from the dense wire.

MOLECULES ALL IN A ROW

Dousing materials with reactive chemicals may not sound like a promising way to make precise nanostructures. But according to researchers in Canada, that simple procedure can be made to work admirably. In laboratories all over the world, scientists are working at developing nanometer-scale electronic devices, chemical sensors, and other hardware for tomorrow's microscopic machinery. Many advances have already been made, but moving nanoscience from great ideas to useful products requires coming up with fast, reliable, and practical fabrication methods as well as procedures for wiring up miniature structures into functioning circuits. Scanning tunneling microscopes (STMs) and related tools have been used in the past few years as tiny tweezers with unparalleled dexterity to build circuit elements from individual atoms. STM manipulations can be extremely accurate spatially, but the atom-at-atime approach used with STMs is too slow to make large numbers of devices quickly. ...

Silicon Field Emitter Array by Fast Anodization Method

ABSTRACTA new fast fabrication method entailing, two step anodization of silicon with different HF solutions was used to form a high aspect ratio silicon Field Emitter Array on n-type silicon (resistivity of 0.01cm). A Silicon oxide mask was used to define the field emitter array. The silicon substrate was pre-anodized with low current density for 1 minute in the dark and then anodized in HF:H2O:Ethanol solution. Finally, the porous silicon was removed by isotropic solution etching. The turn-on voltage of the fabricated field emitters was approximately 27V/μm when the emission current density reaches 1μA/cm2. This compares with the turn-on field of about 35V/μm on silicon tip array fabricated by using an isotropic etching solution of HNO3. We obtained field emitter arrays with good uniformity and reproducibility.

Fast fabrication method for thick and highly multimode optical waveguides

A eutectic melt of lithium and potassium sulphates was used to fabricate thick, low-loss and highly multimode waveguides by ion exchange in glass.