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Jiheng Ding, Obaid Ur Rahman, Hongran Zhao, Wanjun Peng, Huimin Dou, Hao Chen, Haibin Yu
Graphene based films are widely used in the electronics industry. Present work report surface hydroxylated graphene sheets (HGS) from natural graphite by a rapid and efficient molten hydroxide-assisted exfoliated technique. This method enable preparation of a flexible carbon film from exfoliated graphene with extraodinary production yield (~100%), high electrical (11.5×104 S. m-1) and thermal conductivity (1842 W m-1K -1) withbetter dispersion concentration (~10.0 mg mL-1). As a result, this method is expected to applied for the preparation of large-scale, high-quality and low-cost electrical and thermal conductive graphene based material...
July 21, 2017: Nanotechnology
Songling Xing, Luchan Lin, Guisheng Zou, Lei Liu, Peng Peng, Aiping Wu, Walter W Duley, Norman Zhou
In this paper, we show that tightly focused femtosecond laser irradiation is effective in improving nanojoining of an oxide nanowire (TiO2) to a metal electrode (Pt), and how this process can be used to modify contact states. Enhanced chemical bondings are created due to localized plasmonically enhanced optical absorption at the Pt/TiO2 interface as confirmed by finite element simulations of the localized field distribution during irradiation. Nano Auger electron spectroscopy shows that the resulting heterojunction is depleted in oxygen, suggesting that a TiO2-x layer is formed between the Pt electrode and the TiO2 nanowire...
July 21, 2017: Nanotechnology
Moritz Brehm, Martyna Grydlik
In this review, we report on fabrication paths, challenges, and emerging solutions to integrate group-IV epitaxial quantum dots (QDs) as active light emitters into the existing standard Si technology. Their potential as laser gain material for the use of optical intra- and inter-chip interconnects as well as possibilities to combine a single-photon-source-based quantum cryptographic means with Si technology will be discussed. We propose that the mandatory addressability of the light emitters can be achieved by a combination of organized QD growth assisted by templated self-assembly, and advanced inter-QD defect engineering to boost the optical emissivity of group-IV QDs at room-temperature...
July 21, 2017: Nanotechnology
Masoud Dialameh, Federico Ferrarese Lupi, Dario Imbraguglio, Fabio Zanenga, Alessio Lamperti, Davide Martella, Gabriele Seguini, Michele Perego, Andrea Mario Rossi, Natascia De Leo, Luca Boarino
A successful realization of sub 20 nm features on silicon is becoming the focus of many technological studies, strongly influencing the future performance of modern integrated circuits. Although reactive ion etching (RIE), at both micrometric and nanometric scale has already been the target of many studies, a better understanding of the different mechanisms involved at sub 20 nm size etching is still required. In this work, we investigated the influence of the feature size on etch rate of silicon, performed by Cryogenic RIE process through cylinder-forming polystyrene-block-polymethilmetacrhlate (PS-b-PMMA) DiBlock Copolymers (DBCs) masks with diameter ranging between 19 and 13 nm...
July 21, 2017: Nanotechnology
Hyowon Tak, Dongha Tahk, Chanho Jeong, Sori Lee, Tae-Il Kim
We presented surface energy-tunable nanoscale molds for unconventional lithography. The mold is highly robust, transparent, has a minimized haze, does not contain additives, and is a non-fluorinated IDA Isodecyl acrylate (IDA) and Trimethylolpropane Triacrylate (TMPTA) based polymer. By changing the mixing ratio of the polymer components, the cross-linking density, mechanical modulus, and surface energy (crucial factors in low pressure (1~2×105 N/m2) nanoimprint lithography (LP-NIL)), can be controlled. To verify these properties of the molds, we also characterized the surface energy by measuring the contact angles and calculating the work of adhesion among the wafer, polymer film, and mold for successful demolding in nanoscale structures...
July 20, 2017: Nanotechnology
Shahnawaz Phulpoto, Jinhua Sun, Siqi Qi, Linhong Xiao, Shouke Yan, Jianxin Geng
The morphology of electrode materials plays an important role in determining the performance of lithium-ion batteries (LIBs). However, studies on determining the most favorable morphology for high-performance LIBs have rarely been reported. In this study, a series of F-doped SnO<sub>x</sub> (F-SnO<sub>2</sub> and F-SnO) materials with various morphologies was synthesized using ethylenediamine as a structure-directing agent in a facile hydrothermal process. During the hydrothermal process, the F-SnO<sub>x</sub> was embedded <i>in situ</i> into the three-dimensional (3D) architecture of reduced graphene oxide (RGO) to form F-SnO<sub>x</sub>@RGO composites...
July 20, 2017: Nanotechnology
Chao Li, Xiao Yan, Xiongfei Song, Wen-Zhong Bao, Shi-Jin Ding, David Wei Zhang, Peng Zhou
Heterostructure field effect transistors (hetero-FETs) are experimentally demonstrated,consisting of van der Waals heterostructure channels based on two-dimensionalsemiconductor. By optimally selecting the band alignment of heterostructure channels,different output characteristics of the hetero-FETs were achieved. In atomically thinWSe2/MoS2 hetero-FET with staggered energy band, the oscillating transfer characteristic and negative transconductance were realized. With near broken-gap alignment in MoTe2/SnSe2 heterostructure channel, a superior reverse biased current was obtained in the hetero-FETs, which can be analyzed as typical tunnelling current...
July 20, 2017: Nanotechnology
Dhritiman Bhattacharya, Md Mamun Al Rashid, Jayasimha Atulasimha
Recent work [1,2] suggests that ferromagnetic reversal with spin transfer torque (STT) requires more current in a system in the presence of DMI than switching a typical ferromagnet of the same dimensions and perpendicular magnetic anisotropy (PMA). However, DMI promotes stabilization of skyrmions and we report that when the perpendicular anisotropy is modulated (reduced) for both the skyrmion and ferromagnet, it takes much smaller current to reverse the fixed skyrmion than to reverse the ferromagnet in the same time, or the skyrmion reverses much faster than the ferromagnet at similar levels of current...
July 20, 2017: Nanotechnology
Fatemeh Fouladi Mahani, Arash Mokhtari, Mahdiyeh Mehran
Taking advantage of nanostructured metal films as plasmonic colour filters has been evolved remarkably as an alternative to the conventional technologies of chemical colour filtering. However, most of the proposed plasmonic colour filters depict a poor colour purity focusing on the generating of either the additive or subtractive colours. In this paper, we present dual mode operation plasmonic colour filters employing an opaque aluminium film patterned with sub-wavelength holes. Subtractive colours like cyan, magenta, and yellow are the results of reflection mode of these filters yielding optical efficiencies as high as 70-80 percent and full width at half maximum of the stop-bands up to 40-50 nm...
July 20, 2017: Nanotechnology
Kaleem Ahmad, Chunlei Wan
The advancement in nanostructured powder processing has attracted recently great interest as a cost effective and scalable strategy for high performance thermoelectric bulks. However, the level of technical breakthrough as realized in quantum dot supperlattice/wire has not yet demonstrated in these materials. Here, we report first ever study on the uniform dispersion of single wall carbon nanotubes (SWCNTs) in nanostructured Bi2Te3 bulk and their effect on thermoelectric parameters above room temperature. The Bi<sub>2</sub>Te<sub>3</sub> based SWCNTs composites were prepared through controlled powder processing and their thermoelectric properties were finely tuned at nanoscale by regulating various (0...
July 20, 2017: Nanotechnology
Sijia Gu, Xin Zhou, Tianjun Lin, Henri Happy, Tuami Lasri
In this paper, a broadband non-destructive and non-contact local characterization of graphene fabricated by epitaxial method on silicon carbide is demonstrated by using an interferometer-based near-field microwave microscope. First, a method has been proposed to extract the dielectric properties of silicon carbide, and finally, the graphene flake has been characterized as a resistance (∼20 kΩ) and a small inductance (360 pH) in the frequency band (2-18 GHz). The advantage of the proposed method is that there is no need to fabricate electrodes on the sample surface for the characterization...
July 20, 2017: Nanotechnology
Guido Panzarasa, Matthias Dübner, Guido Soliveri, Matthias Edler, Thomas Griesser
Patterning of functional surfaces is one of the cornerstones of nanotechnology as it allows the fabrication of sensors and lab-on-a-chip devices. Here, the patterning of self-assembled monolayers of branched poly(ethyleneimine) (bPEI) on silica was achieved by means of remote photocatalytic lithography. Moreover, when 2-bromoisobutyryl-modified bPEI was used, the resulting pattern could be amplified by grafting polymer brushes by means of surface-initiated atom transfer radical polymerization. In contrast to previous reports for the patterning of bPEI, the present approach can be conducted in minutes instead of hours, reducing the exposure time to UV radiation and enhancing the overall efficiency...
July 20, 2017: Nanotechnology
Nicola Charlotte Grant Black, Chenguang Liu, Ruth Pearce, Bing Li, Stefan Maier, Lesley F Cohen, John C Gallop, Ling Hao
We report a non-contact CVD graphene gas sensing method that utilises a high Q microwave dielectric resonator perturbation technique. A graphene sample is coupled to the evanescent field of a dielectric resonator whereupon nitrogen dioxide (NO2), a p-doping gas, is detected by monitoring the change in the linewidth and frequency of the resonant mode. The resonant peak shape is dependent on the number of carriers in the graphene sheet. Therefore, the linewidth perturbation can be converted to a measurement of the graphene sheet resistance...
July 20, 2017: Nanotechnology
Biswajit Choudhury, Pravat Kumar Giri, Rajender Gone
This work spotlights the development of a plasmonic photocatalyst showing surface plasmon induced enhanced visible light photocatalytic performance. Plasmonic Au nanoparticles (NPs) are decorated over the hybrid nanosystem of graphitic carbon nitride (GCN) and graphene quantum dots (GQD) by citrate reduction method. Surface plasmon resonance (SPR) induced enhancement of Raman G and 2D band intensity is encountered on excitation of the Plasmonic hybrid at 514.5 nm, which is near to the 532 nm absorption band of Au nanoparticles...
July 20, 2017: Nanotechnology
Mochen Li, Xiaohong Zhang, Haibin Jiang, Xiang Wang, Yue Ru, Jinliang Qiao
A new kind of carbon hybrid material with unique structure, outstanding mechanical and functional properties is reported in this article. Nitrogen-doped carbon nanotube arrays with inside located Ni particles are in-situ grown on the surface of phenolic carbon modified graphene fibers during their conversion from graphene oxide fibers. The carbon hybrid fiber exhibits not only high tensile strength and elongation at break, but also excellent flexibility since the carbon nanotube arrays cover the all surface of highly strong graphene fiber...
July 19, 2017: Nanotechnology
Uma Poudyal, Franscis Scott Maloney, Keshab Raj Sapkota, Wenyong Wang
In this work quantum dot sensitized solar cells (QDSSCs) were fabricated with CdSe and Mn-doped CdSe quantum dots (QDs) using the SILAR method. QDSSCs based on Mn-doped CdSe QDs exhibited improved incident photon-to-electron conversion efficiency. Carrier transport dynamics in the QDSSCs were studied using the intensity modulated photocurrent/photovoltage spectroscopy technique, from which transport and recombination time constants could be derived. Compared to CdSe QDSSCs, Mn-CdSe QDSSCs exhibited shorter transport time constant, longer recombination time constant, longer diffusion length, and higher charge collection efficiency...
July 19, 2017: Nanotechnology
Yang Han, Nantao Hu, Shuai Liu, Zhongyu Hou, Jiaqiang Liu, Xiaolin Hua, Zhi Yang, Liangming Wei, Lin Wang, Hao Wei
Nanocoatings of covalent organic frameworks (COFs) on nickel nanowires (NiNWs) have been designed and successfully fabricated for the first time, which showed greatly enhanced electrochemical performances for supercapacitors. The specific capacitance of electrodes based on as-fabricated COFs nanocoatings reached up to 314 F g(-1) at 50 A g(-1), which retained 74% of the specific capacitance under the current density of 2 A g(-1). The ultrahigh current density makes the charge-discharge process extremely rapid...
July 19, 2017: Nanotechnology
Firman Simanjuntak, Sridhar Chandrasekaran, Bhaskar Pattanayak, Chun-Chieh Lin, Tseung-Yuen Tseng
We explore the use of cubic-zinc peroxide (ZnO2) as a switching material for electrochemical metallization memory (ECM) cell. The ZnO2 was synthesized with a simple peroxide surface treatment. Devices made without surface treatment exhibits a high leakage current due to the self-doped nature of the hexagonal-ZnO material. Thus, its switching behavior can only be observed when a very high current compliance is employed. The synthetic ZnO2 layer provides a sufficient resistivity to the Cu/ZnO2/ZnO/ITO devices...
July 19, 2017: Nanotechnology
Song Mi Lee, Sung-Ho Shin, Junghyo Nah, Min Hyung Lee
Appropriate control of energy band bending at the interface between semiconductors and electrolytes are closely related to performance of photoelectrochemical (PEC) water splitting. Dipoles formed near the surface of semiconductors induces energy band bending at the interface. Energy band bending control has been demonstrated by employing charged molecules and piezoelectric materials. However, chemical and piezoelectric approaches have demerit of chemical instability and inducement of instantaneous dipole, respectively...
July 19, 2017: Nanotechnology
Priyam Singh, Praveen Kumar Shahi, Rajiv Prakash, S B Rai
We herein present a novel inorganic-organic hybrid nanoparticle (HNPs) constituted of inorganic NPs, NaY0.78Er0.02Yb0.2F4, and organometallic nanofiber, Tb(ASA)3Phen (TAP). The X-ray diffraction, Fourier transform infrared absorption and TEM analyse reveal that, the prepared ultrafine upconversion nanoparticles {UCNPs (6-9 nm)} are dispersed on the surface of TAP nanofibers. We observe that addition of TAP in UCNPs, effectively prevents the surface quenching to boost the UC intensity and enables tuning of UC emission from green to red region by controlling the phonon frequency around Er3+ ion...
July 18, 2017: Nanotechnology
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