Read by QxMD icon Read

Nano Letters

Ilya Razdolski, Yiguo Chen, Alexander J Giles, Sandy Gewinner, Wieland Schöllkopf, Minghui Hong, Martin Wolf, Vincenzo Giannini, Joshua D Caldwell, Stefan A Maier, Alexander Paarmann
We report on strong enhancement of mid-infrared second harmonic generation (SHG) from SiC nanopillars due to the resonant excitation of localized surface phonon-polaritons within the Reststrahlen band. A strong dependence of the SHG enhancement upon the optical mode distribution was observed. One such mode, the monopole, exhibits an enhancement that is beyond what is anticipated from field localization and dispersion of the linear and nonlinear SiC optical properties. Comparing the results for the identical nanostructures made of 4H and 6H SiC polytypes, we demonstrate the interplay of localized surface phonon polaritons with zone-folded weak phonon modes of the anisotropic crystal...
October 21, 2016: Nano Letters
Gustavo Rios, Evgueniy V Lubenov, Derrick Chi, Michael L Roukes, Athanassios G Siapas
Computations in brain circuits involve the coordinated activation of large populations of neurons distributed across brain areas. However, monitoring neuronal activity in the brain of intact animals with high temporal and spatial resolution has remained a technological challenge. Here we address this challenge by developing dense, three-dimensional (3-D) electrode arrays for electrophysiology. The 3-D arrays constitute the front-end of a modular and configurable system architecture that enables monitoring neuronal activity with unprecedented scale and resolution...
October 21, 2016: Nano Letters
Martin Hetzl, Max Kraut, Julia Winnerl, Luca Francaviglia, Markus Döblinger, Sonja Matich, Anna Fontcuberta I Morral, Martin Stutzmann
We demonstrate the selective area growth of GaN-AlGaN core-shell nanowire heterostructures directly on Si (111). Photoluminescence spectroscopy on as-grown nanowires reveals a strong blueshift of the GaN band gap from 3.40 eV to 3.64 eV at room temperature. Raman measurements relate this shift to compressive strain within the GaN core. On the nano-scale, cathodoluminescence spectroscopy and scanning transmission electron microscopy prove the homogeneity of strain-related luminescence along the NW axis and the absence of significant fluctuations within the shell, respectively...
October 21, 2016: Nano Letters
Xiayin Yao, Deng Liu, Chunsheng Wang, Peng Long, Gang Peng, Yong-Sheng Hu, Hong Li, Liquan Chen, Xiaoxiong Xu
High energy and power densities are the greatest challenge for all-solid-state lithium batteries due to the poor interfacial compatibility between electrodes and electrolytes as well as low lithium ion transfer kinetics in solid materials. Intimate contact at the cathode/solid electrolyte interface and high ionic conductivity of solid electrolyte are crucial to realize high-performance all-solid-state lithium batteries. Here we report a general interfacial architecture, i.e. Li7P3S11 electrolyte particles anchored on cobalt sulfide nanosheets, by an in situ liquid-phase appraoch...
October 21, 2016: Nano Letters
Chong-Rong Wu, Xiang-Rui Chang, Tung-Wei Chu, Hsuan-An Chen, Chao-Hsin Wu, Shih-Yen Lin
A 9-layer WS2/MoS2 hetero-structure is established on a sapphire substrate after sequential growth of large-area and uniform 5- and 4- layer MoS2 and WS2 films by using sulfurization of pre-deposited 1.0 nm Molybdenum (Mo) and Tungsten (W), respectively. By using the results obtained from the ultraviolet photoelectron spectroscopy and the absorption spectrum measurements of the standalone MoS2 and WS2 samples, a type-II band alignment is predicated for the WS2/MoS2 hetero-structure. Increasing drain currents and enhanced field-effect mobility value of the transistor fabricated on the hetero-structure suggested that a channel with higher electron concentration compared with the standalone MoS2 transistor channel is obtained with electron injection from WS2 to MoS2 under thermal equilibrium...
October 20, 2016: Nano Letters
Valentina Zannier, Daniele Ercolani, Umesh Prasad Gomes, Jeremy David, Mauro Gemmi, V G Dubrovskii, Lucia Sorba
Au-catalyzed III-V nanowire heterostructures based on the group III interchange usually grow straight only in one of the two growth sequences, while the other sequence produces kinked geometries, and thus the realization of double heterostructures remains challenging. Here, we investigate the growth of Au-assisted InAs-GaAs and GaAs-InAs axial nanowire heterostructures. A detailed study of the heterostructure morphology as a function of growth parameters and chemical composition of the catalyst nanoparticle is performed by means of scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray analysis...
October 19, 2016: Nano Letters
Stephen R Sanchez, Sergei M Bachilo, Yara Kadria-Vili, Ching-Wei Lin, R Bruce Weisman
A new method based on variance spectroscopy has enabled the determination of absolute absorption cross sections for the first electronic transition of twelve (n,m) structural species of semiconducting single-walled carbon nanotubes (SWCNTs). Spectrally resolved measurements of fluorescence variance in dilute bulk samples provided particle number concentrations of specific SWCNT species. These values were converted to carbon concentrations and correlated with resonant components in the absorbance spectrum to deduce (n,m)-specific absorption cross sections (absorptivities) for nanotubes ranging in diameter from 0...
October 19, 2016: Nano Letters
Xin Yin, Xudong Wang
Nanocrsytal facet evolution is critical for designing nanomaterial morphology and controlling their properties. In this work, we report a unique high-energy crystal facets evolution phenomenon at the tips of Wurtzite zinc oxide nanowires (NWs). As the zinc vapor supersaturation decreased at the NW deposition region, the NW tip facets evolved from the (0001) surface, to the {10-13} surface, and subsequently to the {11-22} surface, and eventually back to the flat (0001) surface. A series of NW tip morphology was observed in accordance to the different combinations of exposed facets...
October 19, 2016: Nano Letters
Andreas Vetter, Simone Ferrari, Patrik Rath, Rasoul Alaee, Oliver Kahl, Vadim Kovalyuk, Silvia Diewald, Gregory N Goltsman, Alexander Korneev, Carsten Rockstuhl, Wolfram Hp Pernice
Ultrafast single-photon detectors with high efficiency are of utmost importance for many applications in the context of integrated quantum photonic circuits. Detectors based on superconductor nanowires attached to optical waveguides are particularly appealing for this purpose. However, their speed is limited because the required high absorption efficiency necessitates long nanowires deposited on top of the waveguide. This enhances the kinetic inductance and makes the detectors slow. Here, we solve this problem by aligning the nanowire, contrary to usual choice, perpendicular to the waveguide to realize devices with a length below 1 µm...
October 19, 2016: Nano Letters
Alon Kosloff, Omri Heifler, Eran Granot, Fernando Patolsky
Here, we demonstrate a novel method for the production of single-crystal Si nanowire arrays based on the top-down carving of Si-nanowall structures from a donor substrate, and their subsequent controlled and selective harvesting into a sacrificial solid material block. Nano-sectioning of the nanostructures-embedding block by ultramicrotome leads to the formation of size, shape and orientation-controlled high quality nanowire arrays. Additionally, we introduce a novel approach that enables transferring the nanowire arrays to any acceptor substrate, while preserving their orientation, and placing them on defined locations...
October 18, 2016: Nano Letters
Thomas Sannicolo, David Muñoz-Rojas, Ngoc Duy Nguyen, Stéphane Moreau, Caroline Celle, Jean-Pierre Simonato, Yves Bréchet, Daniel Bellet
Advancement in the science and technology of random metallic nanowire (MNW) networks is crucial for their appropriate integration in many applications, including transparent electrodes for optoelectronics and transparent film heaters. We have recently highlighted the discontinuous activation of efficient percolating pathways (EPPs) for networks having densities slightly above the percolation threshold. Such networks exhibit abrupt drops of electrical resistance when thermal or electrical annealing is performed, giving rise to a "geometrically quantized percolation"...
October 18, 2016: Nano Letters
Je-Hyung Kim, Christopher J K Richardson, Richard P Leavitt, Edo Waks
Interactions between solid-state quantum emitters and cavities are important for a broad range of applications in quantum communication, linear optical quantum computing, nonlinear photonics, and photonic quantum simulation. These applications often require combining many devices on a single chip with identical emission wavelengths in order to generate two-photon interference, the primary mechanism for achieving effective photon-photon interactions. Such integration remains extremely challenging due to inhomogeneous broadening and fabrication errors that randomize the resonant frequencies of both the emitters and cavities...
October 17, 2016: Nano Letters
Anandram Venkatasubramanian, Vincent T K Sauer, Swapan K Roy, Mike Xia, David S Wishart, Wayne K Hiebert
Micro-Gas Chromatography (GC) is promising for portable chemical analysis. We demonstrate a nano-optomechanical system (NOMS) as an ultrasensitive mass detector in gas chromatography. Bare, native oxide, silicon surfaces are sensitive enough to monitor volatile organic compounds at ppm levels, while simultaneously demonstrating chemical selectivity. The NOMS is able to sense GC peaks from derivatized metabolites at physiological concentrations. This is an important milestone for small-molecule quantitation assays in next generation metabolite analyses for applications such as disease diagnosis and personalized medicine...
October 17, 2016: Nano Letters
Junhui Zhou, Yidi Wu, Changrong Wang, Qiang Cheng, Shangcong Han, Xiaoxia Wang, Jianhua Zhang, Liandong Deng, Deyao Zhao, Lili Du, Huiqing Cao, Zicai Liang, Yuanyu Huang, Anjie Dong
The extremely low efficient cytosolic release of the internalized siRNA has emerged recently as a central issue for siRNA delivery, while there is a lack of guidelines to facilitate the cytosolic release of internalized siRNA. To address these concerns, we studied the contribution of the pH-sensitive inner core on handling the cytosolic release of siRNA delivered by a series of PG-P(DPAx-co-DMAEMAy)-PCB amphiphilic polycation nanomicelles (GDDC-Ms) with extremely low internalization (<1/4 of lipofactamine 2000 (Lipo2000))...
October 17, 2016: Nano Letters
Kyung Min Kim, Jiaming Zhang, Catherine Graves, J Joshua Yang, Byung Joon Choi, Cheol Seong Hwang, Zhiyong Li, R Stanley Williams
A Pt/NbOx/TiOy/NbOx/TiN stack integrated on a 30 nm contact via shows a programming current as low as 10 nA and 1 pA for the set and reset switching, respectively, and a self-rectifying ratio as high as ∼10(5), which are suitable characteristics for low-power memristor applications. It also shows a forming-free characteristic. A charge-trap-associated switching model is proposed to account for this self-rectifying memrisive behavior. In addition, an asymmetric voltage scheme (AVS) to decrease the write power consumption by utilizing this self-rectifying memristor is also described...
October 17, 2016: Nano Letters
Hannes Watzinger, Christoph Kloeffel, Lada Vukušić, Marta D Rossell, Violetta Sessi, Josip Kukučka, Raimund Kirchschlager, Elisabeth Lausecker, Alisha Truhlar, Martin Glaser, Armando Rastelli, Andreas Fuhrer, Daniel Loss, Georgios Katsaros
Hole spins have gained considerable interest in the past few years due to their potential for fast electrically controlled qubits. Here, we study holes confined in Ge hut wires, a so-far unexplored type of nanostructure. Low-temperature magnetotransport measurements reveal a large anisotropy between the in-plane and out-of-plane g-factors of up to 18. Numerical simulations verify that this large anisotropy originates from a confined wave function of heavy-hole character. A light-hole admixture of less than 1% is estimated for the states of lowest energy, leading to a surprisingly large reduction of the out-of-plane g-factors compared with those for pure heavy holes...
October 17, 2016: Nano Letters
Menghao Wu, Shuai Dong, Kailun Yao, Jun-Ming Liu, Xiao Cheng Zeng
Realization of ferroelectric semiconductors by conjoining ferroelectricity with semiconductors remain a challenging task because most present-day ferroelectric materials are unsuitable for such a combination due to their wide bandgaps. Herein we show first-principles evidence towards the realization of a new class of 2D ferroelectric semiconductors through covalent functionalization of many prevailing 2D materials. Members in this new class of 2D ferroelectric semiconductors include covalently functionalized germanene, and stanene (Nat...
October 14, 2016: Nano Letters
Xuezhi Ma, Yangzhi Zhu, Sanggon Kim, Qiushi Liu, Peter Byrley, Yang Wei, Jin Zhang, Kaili Jiang, Shoushan Fan, Ruoxue Yan, Ming Liu
Despite many efforts to fabricate high-aspect-ratio atomic force microscopy (HAR-AFM) probes for high-fidelity, high-resolution topographical imaging of three-dimensional (3D) nano-structured surfaces, current HAR probes still suffer from unsatisfactory performance, low wear-resistivity, and extravagant prices. The primary objective of this work is to demonstrate a novel design of a high-resolution (HR) HAR AFM probe, which is fabricated through a reliable, cost-efficient bench-top process to precisely implant a single ultra-sharp metallic nanowire on a standard AFM cantilever probe...
October 14, 2016: Nano Letters
Yonggang Yao, Kun Fu, Shuze Zhu, Jiaqi Dai, Yanbin Wang, Glenn Pastel, Yanan Chen, Tian Li, Chengwei Wang, Teng Li, Liangbing Hu
Carbon nanomaterials exhibit outstanding electrical and mechanical properties for a range of applications but these superior properties are often compromised as nanomaterials are assembled into bulk structures. This issue of scaling limits the use of carbon nanostructures and can be attributed to poor physical contacts between nanostructures. To address this challenge, we propose a novel technique to build a 3D carbon matrix by forming covalent bonds between carbon nanostructures. In our work, a Joule heating method was developed to bring the carbon nanofiber (CNF) film to temperatures greater than 2500 K at a heating rate of 200 K/minute to fuse together adjacent carbon nanofibers, forming a 3D interconnected carbon network...
October 14, 2016: Nano Letters
Lucas C Flatten, Sotirios Christodoulou, Robin K Patel, Alexander Buccheri, David Martin Coles, Benjamin P L Reid, Robert Anthony Taylor, Iwan Moreels, Jason M Smith
Colloidal semiconductor nanoplatelets exhibit quantum size effects due to their thickness of only few monolayers, together with strong optical band-edge transitions facilitated by large lateral extensions. In this article we demonstrate room temperature strong coupling of the light and heavy hole exciton transitions of CdSe nanoplatelets with the photonic modes of an open planar microcavity. Vacuum Rabi splittings of 66 ± 1 meV and 58 ± 1 meV are observed for the heavy and light hole excitons re- spectively, together with a polariton-mediated hybridisation of both transitions...
October 14, 2016: Nano Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"