Carrier Trap and Their Effects on the Surface and Core of AlGaN/GaN Nanowire Wrap-Gate Transistor.

We used capacitance-voltage (-), conductance-voltage (-), and noise measurements to examine the carrier trap mechanisms at the surface/core of an AlGaN/GaN nanowire wrap-gate transistor (WGT). When the frequency is increased, the predicted surface trap density promptly drops, with values ranging from 9.1 × 10 eV∙cm at 1 kHz to 1.

Inactivation of Escherichia coli O157: H7 in foods by emerging technologies: a review.

Escherichia coli O157: H7 is a representative foodborne pathogen that causes haemorrhagic colitis, bloody diarrhea, and fatal haemolytic uraemic syndrome. Previously, only conventional heat treatment was used to pasteurised food; however, this method decreases food quality, including colour change, denatures proteins, and causes lipid oxidation. Therefore, emerging technologies to inactivate pathogens in food that affect food quality minimally have been researched and developed.

Viscosity-Controllable Graphene Oxide Colloids Using Electrophoretically Deposited Graphene Oxide Sheets.

Graphene oxide (GO) is one of the interesting ink materials owing to its fascinating properties, such as high dissolubility in water and high controllable electric properties. For versatile printing application, the viscosity of GO colloids should be controlled in order to meet the specific process requirements. Here, we report on the relatively rapid fabrication of viscosity-increased GO (VIGO) colloids mixed with electrophoretically deposited GO sheets (EPD-GO).

Evaporation-Rate Control of Water Droplets on Flexible Transparent Heater for Sensor Application.

To develop high-performance de- or anti-frosting/icing devices based on transparent heaters, it is necessary to study the evaporation-rate control of droplets on heater surfaces. However, almost no research has been done on the evaporation-rate control of liquid droplets on transparent heaters. In this study, we investigate the evaporation characteristics of water droplets on transparent heater surfaces and determine that they depend upon the surface wettability, by modifying which, the complete evaporation time can be controlled.

Moisture Effect on Particulate Matter Filtration Performance using Electro-Spun Nanofibers including Density Functional Theory Analysis.

In this study, we use density functional theory (DFT) calculations to investigate the effect of moisture on the performance of three types of nanofiber (NF)-based air-filter media prepared by electrospinning polyvinyl alcohol, polyvinylidene fluoride, and polyacrylonitrile (PAN). Based on the DFT calculations of the intermolecular interactions between the NF-based filter media and water molecules, the PAN-NF filter is expected to exhibit the best performance in the wet state. Experiment studies also successfully demonstrate that the PAN-NF filter medium has better performance in the filtration of particulate matter (PM) than a commercial semi-high efficiency particulate air filter under wet conditions, and these results are in good agreement with the DFT calculation.

Spontaneous Additive Nanopatterning from Solution Route Using Selective Wetting.

Nanopatterns of functional materials have successfully led innovations in a wide range of fields, but further exploration of their full potential has often been limited because of complex and cost-inefficient patterning processes. We here propose an additive nanopatterning process of functional materials from solution route using selective wetting phenomenon. The proposed process can produce nanopatterns as narrow as 150 nm with high yield over large area at ultrahigh process speed, that is, the speed of solution dragging, of up to ca.

Controlled Patterning of Vertical Silicon Structures Using Polymer Lithography and Wet Chemical Etching.

In order to improve their performance for various applications, a facile method for the wafer-scale fabrication of micro/nano-patterned vertical silicon (Si) structures such as silicon nanowires (SiNWs), silicon nanorods (SiNRs), and porous silicon (p-Si) was developed. The method is based on the combination of lithography techniques (photolithography, thermal nano-imprint lithography, nanosphere lithography) and wet chemical etching (electro-chemical etching, metal-assisted chemical etching) processes. Micro-patterned p-Si with various pore diameters from 30 nm to 1.

A facile patterning of silver nanowires using a magnetic printing method.

Patterning of metal nanowires (NWs) is vital for the fabrication of NW-based, high-performance devices such as sensors, transparent conducting electrodes, and optoelectronics. However, the majority of existing patterning methods require complex and expensive technologies. For this reason, we report for the first time a facile and quick patterning method of silver (Ag) NWs using a magnetic printing method.

13.2% efficiency Si nanowire/PEDOT:PSS hybrid solar cell using a transfer-imprinted Au mesh electrode.

Unlabelled: In recent years, inorganic/organic hybrid solar cell concept has received growing attention for alternative energy solution because of the potential for facile and low-cost fabrication and high efficiency. Here, we report highly efficient hybrid solar cells based on silicon nanowires (SiNWs) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (

Pedot: PSS) using transfer-imprinted metal mesh front electrodes. Such a structure increases the optical absorption and shortens the carrier transport distance, thus, it greatly increases the charge carrier collection efficiency.

Rapid Low-Temperature 3D Integration of Silicon Nanowires on Flexible Substrates.

The vertical integration of 1D nanostructures onto the 2D substrates has the potential to offer significant performance gains to flexible electronic devices due to high integration density, large surface area, and improved light absorption and trapping. A simple, rapid, and low temperature transfer bonding method has been developed for this purpose. Ultrasonic vibration is used to achieve a low temperature bonding within a few seconds, resulting in a polymer-matrix-free, electrically conducting vertical assembly of silicon nanowires (SiNWs) with a graphene/PET substrate.

High-durable AgNi nanomesh film for a transparent conducting electrode.

Uniform metal nanomesh structures are promising candidates that may replace of indium-tin oxide (ITO) in transparent conducting electrodes (TCEs). However, the durability of the uniform metal mesh has not yet been studied. For this reason, a comparative analysis of the durability of TCEs based on pure Ag and AgNi nanomesh, which are fabricated by using simple transfer printing, is performed.

Polymer-free Vertical Transfer of Silicon Nanowires and their Application to Energy Storage.

Silicon nanowires (SiNWs) for use as lithium-ion battery (LIB) anode materials have been studied for their one-dimensional (1D) properties and ability to accommodate large volume changes and avoid rapid capacity fading during cycling. Although the vertical transfer of SiNWs from their original substrate onto a conducting electrode is very important, to date, there has been no report of a direct integration method without polymer binders. Here, we propose for the first time a vertical transfer method for SiNWs grown on a Si substrate directly to the current-collecting electrode without using a polymer adhesive for the use as a binder-free LIB anode.

Highly robust silicon nanowire/graphene core-shell electrodes without polymeric binders.

A large theoretical charge storage capacity along with a low discharge working potential renders silicon a promising anode material for high energy density lithium ion batteries. However, up to 400% volume expansion during charge-discharge cycling coupled with a low intrinsic electronic conductivity causes pulverization and fracture, thus inhibiting silicon's widespread use in practical applications. We report herein on a low cost approach to fabricate hybrid silicon nanowire (SiNW)/graphene nanostructures that exhibit enhanced cycle performance with the capability of retaining more than 90% of their initial capacity after 50 cycles.

Superamphiphobic surface by nanotransfer molding and isotropic etching.

We present a novel method of fabricating superhydrophobic and superoleophobic surfaces with nanoscale reentrant curvature by nanotransfer molding and controlled wet etching of the facile undercut. This method produces completely ordered re-entrant nanostructures and prevents capillary-induced bundling effects. The mushroom-like, re-entrant, overhanging structure demonstrates superhydrophobic and superoleophobic characteristics, as tested by water droplet bouncing and contact angle measurements, and has high transparency on a flexible substrate.

A micro-system based on glass-nanoporous silicon for optical sensing of organic solvent vapor.

We present a recent experimental study on the application of nanoporous silicon (np-Si) to an optical vapor sensor. We fabricated the micro-system based on a glass-nanoporous silicon layer on a p(+)-type silicon wafer. To check the selectivity and sensitivity of the np-Si layer to organic vapors, we prepared three types of np-Si layer samples--a single layer, distributed Bragg reflector (DBR) layer, and microcavity layer--and investigated its reflectance spectra upon exposure to different concentrations of various organic vapors.

Nano-engineered optimal templates for surface-plasmon enhanced Raman scattering.

We investigated the critical conditions to realize reliable and nano-engineered templates for surface-plasmon enhanced Raman scattering (SERS). Ultra-sensitive SERSs of thymine oligonucleotides were successfully realized on the template of Au nanoparticle arrays which were prepared by the combination of electron-beam lithography and post-chemical modification techniques. Drastic enhancement of Raman signal from the thymine oligonucleotides was only observed on the optimized templates, where the tuning of the plasmon resonance condition and the formation of the hot spots were both critical.

Clinical approach to the standardization of oriental medical diagnostic pattern identification in stroke patients.

In Korea, many stroke patients receive oriental medical care, in which pattern-identification plays a major role. Pattern-identification is Oriental Medicine's unique diagnostic system. This study attempted to standardize oriental medical pattern-identification for stroke patients.