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enhancer insulator

Ching-Lin Fan, Fan-Ping Tseng, Chiao-Yuan Tseng
In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a HfO₂ gate insulator and CF₄ plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO₂ gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm²/V∙s (without treatment) to 54.6 cm²/V∙s (with CF₄ plasma treatment), which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density...
May 17, 2018: Materials
Ailing Chen, Daozhen Chen, Ying Chen
Expression of the eukaryotic genome is a highly complex and tightly regulated process, and its regulation depends on interactions among cis-acting elements and transcription factors. Identification of active gene regulatory elements is key to understanding transcriptional control of biological processes including differentiation, development, proliferation, cell-type specificity, and responses to the environment. DNase I hypersensitive sites (DHSs) are markers of open chromatin that provide a very effective method of targeting all types of cis-regulatory elements (CREs) including enhancers, promoters, insulators, silencers, and locus control regions...
May 14, 2018: Gene
Ryota Akiyama, Kazuki Sumida, Satoru Ichinokura, Ryosuke Nakanishi, Akio Kimura, Konstantin A Kokh, Oleg Tereshchenko, Shuji Hasegawa
We show Shubnikov-de Haas (SdH) oscillations in topological insulator (Bi<sub>x</sub>Sb<sub>1-x</sub>)<sub>2</sub>Te<sub>3</sub> flakes whose carrier types are <i>p</i>-type (<i>x</i> = 0.29, 0.34) and <i>n</i>-type (<i>x</i> = 0.42). The physical properties such as the Berry phase, carrier mobility, and scattering time significantly changed by tuning the Fermi-level position with the concentration <i>x</i>...
May 17, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Jinho Lee, Chibeom Park, Intek Song, Jin Young Koo, Taekyung Yoon, Jun Sung Kim, Hee Cheul Choi
In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K2 picene single crystal, while only parts of the crystal are doped and transformed into K2 picene without secondary thermal activation...
May 16, 2018: Scientific Reports
Huacheng Luo, Fei Wang, Jie Zha, Haoli Li, Bowen Yan, Qinghua Du, Fengchun Yang, Amin Sobh, Christopher Vulpe, Leylah Drusbosky, Christopher Cogle, Iouri Chepelev, Bing Xu, Stephen D Nimer, Jonathan Licht, Yi Qiu, Baoan Chen, Mingjiang Xu, Suming Huang
HOX gene dysregulation is a common feature of acute myeloid leukemia (AML). The molecular mechanisms underlying aberrant HOX gene expression and associated AML pathogenesis remain unclear. The nuclear protein CCCTC-binding factor (CTCF), when bound to insulator sequences, constrains temporal HOX gene expression patterns within confined chromatin domains for normal development. Here, we employed targeted pooled CRISPR-Cas9 knockout library screening to interrogate the function of CTCF boundaries in the HOX gene loci...
May 14, 2018: Blood
M Z Li, Z H Wang, L Yang, D S Pan, Da Li, Xuan Gao, Zhi-Dong Zhang
Controlling the growth direction (planar vs. vertical) and surface-to-bulk ratio can lead to lots of unique properties for two-dimensional (2D) layered materials. We report a simple method to fabricate continuous films of vertical Bi2Se3 nanoplates on Si substrate and investigate the quantum transport properties of such films. In contrast to (001) oriented planar Bi2Se3 nanoplate film, vertical Bi2Se3 nanoplate films are enclosed by (015) facets, which possess high surface-to-bulk ratio that can enhance the quantum transport property of topological surface states...
May 14, 2018: Nanotechnology
Bryan J Matthews, David J Waxman
CTCF and cohesin are key drivers of 3D-nuclear organization, anchoring the megabase-scale Topologically Associating Domains (TADs) that segment the genome. Here, we present and validate a computational method to predict cohesin-and-CTCF binding sites that form intra-TAD DNA loops. The intra-TAD loop anchors identified are structurally indistinguishable from TAD anchors regarding binding partners, sequence conservation, and resistance to cohesin knockdown; further, the intra-TAD loops retain key functional features of TADs, including chromatin contact insulation, blockage of repressive histone mark spread, and ubiquity across tissues...
May 14, 2018: ELife
Taylor P Allred, Justin A Weibel, Suresh V Garimella
A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency...
April 27, 2018: Physical Review Letters
Seung Woon Baek, Jong-Woon Ha, Minho Yoon, Do-Hoon Hwang, Jiyoul Lee
Shellac, a natural polymer resin obtained from the secretions of lac bugs, was evaluated as a dielectric layer in organic field-effect transistors (OFETs) on the basis of donor (D)-acceptor (A)-type conjugated semiconducting copolymers. The measured dielectric constant and breakdown field of the shellac layer were ~3.4 and 3.0 MV/cm, respectively, comparable with those of a poly(4-vinylphenol) (PVP) film, a commonly used dielectric material. Bottom-gate/top-contact (BG/TC) OFETs were fabricated with shellac or PVP as the dielectric layer and one of three different D-A-type semiconducting copolymers as the active layer: poly(cyclopentadithiophene-alt-benzothiadiazole) [P(CDT-BTZ)] with p-type characteristics, poly(naphthalene-bis(dicarboximide)-alt-bithiophene) [P(NDI2OD-T2)] with n-type characteristics, and poly(dithienyl-diketopyrrolopyrrole-alt-thienothiophene) [P(DPP2T-TT)] with ambipolar characteristics...
May 14, 2018: ACS Applied Materials & Interfaces
Minchul Kim, Hagen Wende, Jan Walcher, Johannes Küehnemund, Cyril Cheret, Stefan Kempa, Erik McShane, Matthias Selbach, Gary R Lewin, Carmen Birchmeier
Cholesterol is a major constituent of myelin membranes, which insulate axons and allow saltatory conduction. Therefore, Schwann cells, the myelinating glia of the peripheral nervous system, need to produce large amounts of cholesterol. Here, we define a crucial role of the transcription factor Maf in myelination and cholesterol biosynthesis and show that Maf acts downstream from Neuregulin1 (Nrg1). Maf expression is induced when Schwann cells begin myelination. Genetic ablation of Maf resulted in hypomyelination that resembled mice with defective Nrg1 signaling...
May 10, 2018: Genes & Development
Mahdi Hamidinejad, Biao Zhao, Raymond K M Chu, Nima Moghimian, Hani E Naguib, Tobin Filleter, Chul B Park
Dielectric polymer nanocomposites with high dielectric constant (ε'), and low dielectric loss (tan δ) are extremely desirable in the electronics industry. Percolative polymer-graphene nanoplatelet (GnP) composites have shown great promise as dielectric materials for high-performance capacitors. Herein an industrially-viable technique for manufacturing a new class of ultralight polymer composite foams using commercial GnPs with excellent dielectric performance is presented. Using this method, the high-density polyethylene (HDPE)-GnPs composites with a microcellular structure were fabricated by melt mixing...
May 10, 2018: ACS Applied Materials & Interfaces
Ruoting Dong, Changyong Lan, Xiuwen Xu, Xiaoguang Liang, Xiaoying Hu, Dapan Li, Ziyao Zhou, Lei Shu, SenPo Yip, Chun Li, Sai-Wing Tsang, Johnny C Ho
Quasi two-dimensional (2D) layered organic-inorganic perovskite materials (e.g. (BA)2 (MA)n-1 Pbn I3n+1 ; BA = butylamine; MA = methylamine), have recently attracted a wide attention due to their superior moisture stability as compared with three-dimensional counterparts. Inevitably, hydrophobic yet insulating long-chained organic cations improve the stability at the cost of hindering charge transport, leading to the unsatisfied performance of subsequently fabricated devices. Here, we reported the synthesis of quasi-2D (iBA)2 (MA)n-1 Pbn I3n+1 perovskites, where the relatively pure phase (iBA)2 PbI4 and (iBA)2 MA3 Pb4 I13 films can be obtained...
May 9, 2018: ACS Applied Materials & Interfaces
M E Manley, P J Stonaha, D L Abernathy, S Chi, R Sahul, R P Hermann, J D Budai
Controlling the thermal energy of lattice vibrations separately from electrons is vital to many applications including electronic devices and thermoelectric energy conversion. To remove heat without shorting electrical connections, heat must be carried in the lattice of electrical insulators. Phonons are limited to the speed of sound, which, compared to the speed of electronic processes, puts a fundamental constraint on thermal management. Here we report a supersonic channel for the propagation of lattice energy in the technologically promising piezoelectric mineral fresnoite (Ba2 TiSi2 O8 ) using neutron scattering...
May 8, 2018: Nature Communications
Yifei Shi, Wen Wu, Hua Dong, Guangru Li, Kai Xi, Giorgio Divitini, Chenxin Ran, Fang Yuan, Min Zhang, Bo Jiao, Xun Hou, Zhaoxin Wu
All present designs of perovskite light-emitting diodes (PeLEDs) stem from polymer light-emitting diodes (PLEDs) or perovskite solar cells. The optimal structure of PeLEDs can be predicted to differ from PLEDs due to the different fluorescence dynamics and crystallization between perovskite and polymer. Herein, a new design strategy and conception is introduced, "insulator-perovskite-insulator" (IPI) architecture tailored to PeLEDs. As examples of FAPbBr3 and MAPbBr3 , it is experimentally shown that the IPI structure effectively induces charge carriers into perovskite crystals, blocks leakage currents via pinholes in the perovskite film, and avoids exciton quenching simultaneously...
May 7, 2018: Advanced Materials
Zai-Xing Yang, Yanxue Yin, Jiamin Sun, Luozhen Bian, Ning Han, Ziyao Zhou, Lei Shu, Fengyun Wang, Yunfa Chen, Aimin Song, Johnny C Ho
Recently, owing to the large surface-area-to-volume ratio of nanowires (NWs), manipulation of their surface states becomes technologically important and being investigated for various applications. Here, an in-situ surfactant-assisted chemical vapor deposition is developed with various chalcogens (e.g. S, Se and Te) as the passivators to enhance the NW growth and to manipulate the controllable p-n conductivity switching of fabricated NW devices. Due to the optimal size effect and electronegativity matching, Se is observed to provide the best NW surface passivation in diminishing the space charge depletion effect induced by the oxide shell and yielding the less p-type (i...
May 2, 2018: Scientific Reports
Joshua R St Clair, David Ramirez, Samantha Passman, Richard K P Benninger
In type 1 diabetes (T1D), immune-cell infiltration into the islets of Langerhans (insulitis) and β-cell decline occurs many years before diabetes clinically presents. Non-invasively detecting insulitis and β-cell decline would allow the diagnosis of eventual diabetes, and provide a means to monitor therapeutic intervention. However, there is a lack of validated clinical approaches for specifically and non-invasively imaging disease progression leading to T1D. Islets have a denser microvasculature that reorganizes during diabetes...
May 1, 2018: Nature Communications
Xin Luo, Xiang Zhai, Lingling Wang, Qi Lin
In order to remarkably enhance its absorption capability, a tunable dual-band MoS2 -based perfect absorber inspired by metal-insulator-metal (MIM) metamaterial is proposed. By using the finite-difference time-domain (FDTD) simulations, dual-band perfect absorption peaks are realized in the visible light regime, and the absorptions of monolayer MoS2 are enhanced up to 57% and 80.5% at the peak wavelengths. By manipulating related structural parameters, the peak wavelengths of MoS2 absorption can be separately tuned in a wide wavelength range...
April 30, 2018: Optics Express
Wei Wang, Dian Lei, Yi-Chiau Huang, Kwang Hong Lee, Wan-Khai Loke, Yuan Dong, Shengqiang Xu, Chuan Seng Tan, Hong Wang, Soon-Fatt Yoon, Xiao Gong, Yee-Chia Yeo
We report the first demonstration of high-performance GeSn metal-semiconductor-metal (MSM) photodetector and GeSn p-type fin field-effect transistor (pFinFET) on an advanced GeSn-on-insulator (GeSnOI) platform by complementary metal-oxide-semiconductor (CMOS) compatible processes. The detection range of GeSn photodetector is extended beyond 2 µm, with responsivities of 0.39 and 0.10 A/W at 1550 nm and 2003 nm, respectively. Through the insertion of an ultrathin Al2 O3 Schottky-barrier-enhancement layer, the dark current IDark of the GeSn photodetector is suppressed by more than 2 orders of magnitude...
April 16, 2018: Optics Express
Linda M Guiney, Nikhita D Mansukhani, Adam E Jakus, Shay G Wallace, Ramille N Shah, Mark C Hersam
Hexagonal boron nitride (hBN) is a thermally conductive yet electrically insulating two-dimensional layered nanomaterial that has attracted significant attention as a dielectric for high-performance electronics in addition to playing a central role in thermal management applications. Here, we report a high-content hBN-polymer nanocomposite ink, which can be 3D printed to form mechanically robust, self-supporting constructs. In particular, hBN is dispersed in poly(lactic-co-glycolic acid) and 3D printed at room temperature through an extrusion process to form complex architectures...
April 30, 2018: Nano Letters
Xu Wang, Joseph Schwan, Noah Hood, Hsiang-Wen Hsu, Eberhard Grün, Mihály Horányi
Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using three recently developed experiments in which dust particles are exposed to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. The UV light source has a narrow bandwidth in wavelength centered at 172 nm. The beam electrons with the energy of 120 eV are created with a negatively biased hot filament. When the vacuum chamber is filled with the argon gas, a thermal plasma is created in addition to the electron beam...
April 3, 2018: Journal of Visualized Experiments: JoVE
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