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enhancer insulator

Benjamin T Hogan, Sergey A Dyakov, Lorcan J Brennan, Salma Younesy, Tatiana S Perova, Yurii K Gun'ko, Monica F Craciun, Anna Baldycheva
In this work, we propose a novel approach for wafer-scale integration of 2D materials on CMOS photonic chip utilising methods of synthetic chemistry and microfluidics technology. We have successfully demonstrated that this approach can be used for integration of any fluid-dispersed 2D nano-objects on silicon-on-insulator photonics platform. We demonstrate for the first time that the design of an optofluidic waveguide system can be optimised to enable simultaneous in-situ Raman spectroscopy monitoring of 2D dispersed flakes during the device operation...
February 10, 2017: Scientific Reports
Sina Abedini Dereshgi, Zulkarneyn Sisman, Kagan Topalli, Ali Kemal Okyay
Plasmonically enhanced metal-insulator-metal (MIM) type structures are popular among perfect absorbers and photodetectors in which the field enhancement (for increased absorption) mechanism is directly coupled with collection (photocurrent) processes. In this work we propose a device structure that decouples absorption and collection parts for independent optimization. Double-stacked MIM (i.e. MIMIM) photodetectors operating in the near-infrared (NIR) spectrum up to 1200 nm wavelength are demonstrated. In the absorbing MIM (at the top side), we have used Silver nanoparticles resulting from dewetting, yielding a very low reflection of 10% for the most part of the 400 to 1000 nm wavelength range...
February 9, 2017: Scientific Reports
Bo-Wei Chen, Ting-Chang Chang, Yu-Ju Hung, Shin-Ping Huang, Hua-Mao Chen, Po-Yung Liao, Yu-Ho Lin, Hui-Chun Huang, Hsiao-Cheng Chiang, Chung-I Yang, Yu-Zhe Zheng, Ann-Kuo Chu, Hung-Wei Li, Chih-Hung Tsai, Hsueh-Hsing Lu, Terry Tai-Jui Wang, Tsu-Chiang Chang
Surface morphology in polycrystalline silicon (poly-Si) film is an issue regardless of whether conventional excimer laser annealing (ELA) or the newer metal-induced lateral crystallization (MILC) process is used. This paper investigates the stress distribution while undergoing long-term mechanical stress and the influence of stress on electrical characteristics. Our simulated results show that the non-uniform stress in the gate insulator is more pronounced near the polysilicon/gate insulator edge and at the two sides of the polysilicon protrusion...
February 8, 2017: ACS Applied Materials & Interfaces
Kundan Sivashanmugan, Po-Chun Liu, Kai-Wei Tsai, Ying-Nien Chou, Chen-Hsueh Lin, Yung Chang, Ten-Chin Wen
In bioenvironmental detection, surface-enhanced Raman scattering (SERS) signals are greatly affected by anti-specific biomolecule adsorption, which generates strong background noise, reducing detection sensitivity and selectivity. It is thus necessary to modify the SERS substrate surface to make it anti-fouling to maintain excellent SERS signals. Herein, we propose a zwitterionic copolymer, namely poly(glycidyl methacrylate-co-sulfobetaine methacrylate) (poly(GMA-co-SBMA)), for the surface modification of SERS substrates, which were fabricated and characterized spectroscopically...
February 7, 2017: Nanoscale
Rajendra Dhakal, E S Kim, Yong-Hwa Jo, Sung-Soo Kim, Nam-Young Kim
We present a concept for the characterization of micro-fabricated based resonator incorporating air-bridge metal-insulator-semiconductor (MIS) capacitor to continuously monitor an individual's state of glucose levels based on frequency variation. The investigation revealed that, the micro-resonator based on MIS capacitor holds considerable promise for implementation and recognition as a glucose sensor for human serum. The discrepancy in complex permittivity as a result of enhanced capacitor was achieved for the detection and determination of random glucose concentration levels using a unique variation of capacitor that indeed results in an adequate variation of the resonance frequency...
January 31, 2017: Medical Engineering & Physics
Domenico Di Sante, Simone Fratini, Vladimir Dobrosavljević, Sergio Ciuchi
We show that, in the presence of a deformable lattice potential, the nature of the disorder-driven metal-insulator transition is fundamentally changed with respect to the noninteracting (Anderson) scenario. For strong disorder, even a modest electron-phonon interaction is found to dramatically renormalize the random potential, opening a mobility gap at the Fermi energy. This process, which reflects disorder-enhanced polaron formation, is here given a microscopic basis by treating the lattice deformations and Anderson localization effects on the same footing...
January 20, 2017: Physical Review Letters
Maxim Varenik, Roey Nadiv, Idan Levy, Gleb Vasilyev, Oren Regev
Thermal conductivity (TC) enhancement of an insulating polymer matrix at low filler concentration is possible through the loading of a high aspect ratio, thermally conductive single filler. Unfortunately, the dispersion of high-aspect-ratio particles greatly influences the rheological behavior of the polymer host at relatively low volume fractions, which makes further polymer processing or mixing difficult. A possible remedy is using two (hybrid) fillers, differing in their aspect ratios: (1) a plate-like filler, which sharply increases both viscosity and TC, and (2) an isotropic filler, which gradually increases these properties...
February 15, 2017: ACS Applied Materials & Interfaces
Xingwei Ding, Cunping Qin, Jiantao Song, Jianhua Zhang, Xueyin Jiang, Zhilin Zhang
Thin-film transistors (TFTs) with atomic layer deposition (ALD) HfZnO (HZO) as channel layer and Al2O3 as gate insulator were successfully fabricated. Compared with ZnO-TFT, the stability of HZO-TFT was obviously improved as Hf doping can suppress the generation of oxygen related defects. The transfer characteristics of TFTs at different temperatures were also investigated, and temperature stability enhancement was observed for the TFT with Hf doping. The density of states (DOS) was calculated based on the experimentally obtained E a, which can explain the experimental observation...
December 2017: Nanoscale Research Letters
Kyungtaek Min, Muhammad Umar, Shinyoung Ryu, Soonil Lee, Sunghwan Kim
Ultra-thin and ultra-smooth gold (Au) films are appealing for photonic applications including surface plasmon resonances and transparent contacts. However, poor adhesion at the Au-dielectric interface prohibits the formation of a mechanically stable, ultra-thin, and ultra-smooth Au film. A conventional solution is to use a metallic adhesion layer, such as titanium and chromium, however such layers cause the optical properties of pure Au to deteriorate. Here we report the use of silk protein to enhance the adhesion at the Au-dielectric interface, thus obtaining ultra-smooth sub-10 nm Au films...
January 19, 2017: Nanotechnology
Hannes Hübener, Michael A Sentef, Umberto De Giovannini, Alexander F Kemper, Angel Rubio
Tuning and stabilizing topological states, such as Weyl semimetals, Dirac semimetals or topological insulators, is emerging as one of the major topics in materials science. Periodic driving of many-body systems offers a platform to design Floquet states of matter with tunable electronic properties on ultrafast timescales. Here we show by first principles calculations how femtosecond laser pulses with circularly polarized light can be used to switch between Weyl semimetal, Dirac semimetal and topological insulator states in a prototypical three-dimensional (3D) Dirac material, Na3Bi...
January 17, 2017: Nature Communications
S Manna, A Kamlapure, L Cornils, T Hänke, E M J Hedegaard, M Bremholm, B B Iversen, Ph Hofmann, J Wiebe, R Wiesendanger
The discovery of high-temperature superconductivity in Fe-based compounds triggered numerous investigations on the interplay between superconductivity and magnetism, and on the enhancement of transition temperatures through interface effects. It is widely believed that the emergence of optimal superconductivity is intimately linked to the suppression of long-range antiferromagnetic (AFM) order, although the exact microscopic picture remains elusive because of the lack of atomically resolved data. Here we present spin-polarized scanning tunnelling spectroscopy of ultrathin FeTe1-xSex (x=0, 0...
January 17, 2017: Nature Communications
Soudabeh Mashhadi, Dinh Loc Duong, Marko Burghard, Klaus Kern
Tuning the electron and phonon transport properties of thermoelectric materials by nanostructuring has enabled improving their thermopower figure of merit. Three-dimensional topological insulators, including many bismuth chalcogenides, attract increasing attention for this purpose, as their topologically protected surface states are promising to further enhance the thermoelectric performance. While individual bismuth chalcogenide nanostructures have been studied with respect to their photothermoelectric properties, nanostructured p-n junctions of these compounds have not yet been explored...
January 11, 2017: Nano Letters
Yanbo Li, Yukun Ren, Weiyu Liu, Xiaoming Chen, Ye Tao, Hongyuan Jiang
In this study, we develop a nondimensional physical model to demonstrate fluid flow at the micrometer dimension driven by traveling-wave induction electrohydrodynamics (EHD) through direct numerical simulation. In order to realize an enhancement in the pump flow rate as well as a flexible adjustment of anisotropy of flow behavior generated by induction EHD in microchannels, while not adding the risk of causing dielectric breakdown of working solution and material for insulation, a pair of synchronized traveling-wave voltage signals are imposed on double-sided electrode arrays that are mounted on the top and bottom insulating substrate, respectively...
January 9, 2017: Electrophoresis
Junjun Zhang, Wenpei Kang, Miao Jiang, Yu You, Yulin Cao, Tsz-Wai Ng, Denis Y W Yu, Chun-Sing Lee, Jun Xu
S-Doped 2H-MoSe2 (i.e., 2H-MoS2xSe2-2x) mesoporous nanospheres assembled from several-layered nanosheets are synthesized by sulfurizing freshly-prepared 1T-MoSe2 nanospheres, and they serve as a robust host material for sodium storage. The sulfuration treatment is found to be beneficial for removing surface/interface insulating organic contaminants and converting the 1T phase to the 2H phase with improved crystallinity and electrical conductivity. These result in significantly enhanced sodium storage performance, including charge/discharge capacity, first Coulombic efficiency, cycling stability, and rate capability...
January 9, 2017: Nanoscale
Susan J Burke, Heidi M Batdorf, Adrianna E Eder, Michael D Karlstad, David H Burk, Robert C Noland, Z Elizabeth Floyd, J Jason Collier
Steroid-induced diabetes is the most common form of drug-induced hyperglycemia. Therefore, metabolic and immunological alterations associated with chronic oral corticosterone were investigated using male nonobese diabetic mice. Three weeks after corticosterone delivery, there was reduced sensitivity to insulin action measured by insulin tolerance test. Body composition measurements revealed increased fat mass and decreased lean mass. Overt hyperglycemia (>250 mg/dL) manifested 6 weeks after the start of glucocorticoid administration, whereas 100% of the mice receiving the vehicle control remained normoglycemic...
January 4, 2017: American Journal of Pathology
Guangwei Cong, Morifumi Ohno, Yuriko Maegami, Makoto Okano, Koji Yamada
Optical autocorrelation accuracy was for the first time analyzed for the silicon waveguide based autocorrelators utilizing two-photon absorption (TPA) under various short pulse conditions by numerical simulation. As for autocorrelation operation in the sub-μm silicon p-i-n rib waveguides on the 220 nm SOI (silicon on insulator) wafers, the autocorrelation error of pulse width measurement gradually increases with the increase of the peak power for both Gaussian and hyperbolic secant pulses due to the influence of free-carrier absorption (FCA)...
December 26, 2016: Optics Express
Carlito Baltazar Tabelin, Suchol Veerawattananun, Mayumi Ito, Naoki Hiroyoshi, Toshifumi Igarashi
The oxidative dissolution of pyrite is an important process in the redox recycling of iron (Fe) and is well-known for its role in the formation of acid mine drainage (AMD), which is considered as the most serious and widespread problem after the closure of mines and mineral processing operations. Because this process requires the movement of electrons, common metal oxides in nature that have either semiconducting (e.g., hematite) or insulating (e.g., alumina) properties may have strong effects on it. In this study, changes in the electrochemical behavior of pyrite in the presence of hematite and alumina were investigated...
January 3, 2017: Science of the Total Environment
Alex Risos, Nicholas Long, Arvid Hunze, Gideon Gouws
Interdigitated dielectrometry sensors (IDS) are capacitive sensors investigated to precisely measure the relative permittivity ( ϵ r ) of insulating liquids. Such liquids used in the power industry exhibit a change in ϵ r as they degrade. The IDS ability to measure ϵ r in-situ can potentially reduce maintenance, increase grid stability and improve safety. Noise from external electric field sources is a prominent issue with IDS. This paper investigates the novelty of applying a Faraday cage onto an IDS as a 3D shield to reduce this noise...
December 31, 2016: Sensors
Hongzhen Liu, Yanyan Lou, Siriporn Jungsuttiwong, Shuai Yuan, Yin Zhao, Zhuyi Wang, Liyi Shi, Hualan Zhou
Charge recombination and transfer at the TiO2/dye/electrolyte interface play a crucial role in dye-sensitized solar cells (DSSCs). Here, a fine-controlled gold nanoparticle (Au NP) via electrodeposition incorporated into a porous TiO2 photoanode and dodecanethiol molecules as an assembled monolayer capping on Au NPs was designed and prepared. The "fence-like" structure of gold thiol molecules at the TiO2/dye/electrolyte interface can not only insulate the electrolyte to suppress recombination but also make full use of the plasmon-enhanced light absorption of Au NPs...
January 11, 2017: ACS Applied Materials & Interfaces
Jin Hee Lee, Hamza Zad Gul, Hyun Kim, Byoung Hee Moon, Subash Adhikari, Jung Ho Kim, Homin Choi, Young Hee Lee, Seong Chu Lim
We achieve switching on/off the photocurrent of monolayer molybdenum disulfide (MoS2) by controlling the metal-insulator transition (MIT). N-type semiconducting MoS2 under a large negative gate bias generates a photocurrent attributed to the increase of excess carriers in the conduction band by optical excitation. However, under a large positive gate bias, a phase shift from semiconducting to metallic MoS2 is caused, and the photocurrent by excess carriers in the conduction band induced by the laser disappears due to enhanced electron-electron scattering...
January 3, 2017: Nano Letters
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