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Sample records for single nanostructure ssn

  1. Suspended and localized single nanostructure growth across a nanogap by an electric field

    International Nuclear Information System (INIS)

    Lee, Chung-Hoon; Schneider, Susan C; Josse, Fabien; Han, Jun Hyun

    2011-01-01

    Direct growth of a suspended single nanostructure (SSN) at a specific location is presented. The SSN is grown across a metallic nanoscale gap by migration in air at room temperature. The nanogap is fabricated by industrial standard optical lithography and anisotropic wet chemical silicon etching. A DC current bias, 1 nA, is applied across the metallic gap to induce nanoscale migration of Zn or ZnO. The history of the voltage drop across the gap as a function of time clearly indicates the moment when migration begins. The shape of SSNs grown across the nanogap by the migration is asymmetric at each electrode due to the asymmetric electric field distribution within the nanogap. An SSN can be used as the platform for two-terminal active or passive nanoscale electronics in optoelectronics, radio frequency (RF) resonators, and chemical/biological sensors.

  2. SSN Verification Service

    Data.gov (United States)

    Social Security Administration — The SSN Verification Service is used by Java applications to execute the GUVERF02 service using the WebSphere/CICS Interface. It accepts several input data fields...

  3. Propagation of plasmons in designed single crystalline silver nanostructures

    DEFF Research Database (Denmark)

    Kumar, Shailesh; Lu, Ying-Wei; Huck, Alexander

    2012-01-01

    We demonstrate propagation of plasmons in single crystalline silver nanostructures fabricated using a combination of a bottom-up and a top-down approach. Silver nanoplates of thickness around 65 nm and a surface area of about 100 μm2 are made using a wet chemical method. Silver nanotips...

  4. Atomically flat single-crystalline gold nanostructures for plasmonic nanocircuitry

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J S; Geisler, P; Bruening, C; Kern, J; Prangsma, J C; Wu, X; Feichtner, Thorsten; Ziegler, J; Weinmann, P; Kamp, M; Forchel, A; Hecht, B [Wilhelm-Conrad-Roentgen-Center for Complex Material Systems, University of Wuerzburg (Germany); Biagioni, P [CNISM, Dipartimento di Fisica, Politecnico di Milano (Italy)

    2011-07-01

    Deep subwavelength integration of high-definition plasmonic nano-structures is of key importance for the development of future optical nanocircuitry. So far the experimental realization of proposed extended plasmonic networks remains challenging, mainly due to the multi-crystallinity of commonly used thermally evaporated gold layers. Resulting structural imperfections in individual circuit elements drastically reduce the yield of functional integrated nanocircuits. Here we demonstrate the use of very large but thin chemically grown single-crystalline gold flakes. After immobilization on any arbitrary surface, they serve as an ideal basis for focused-ion beam milling. We present high-definition ultra-smooth gold nanostructures with reproducible nanosized features over micrometer lengthscales. By comparing multi- and single-crystalline optical antennas we prove that the latter have superior optical properties which are in good agreement with numerical simulations.

  5. Stability of sp{sup 2}-carbon single layer nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, L N; Bursill, L A [University of Melbourne, Parkville, VIC (Australia). School of Physics

    1997-12-31

    Full text: Sp{sup 2}-hybridised carbon is quite versatile in its ability to build atomic structures. Although graphite is the most common and best known sp{sup 2}-carbon compound, recent discoveries of the C{sub 60} molecule and the related nanotubes have shown that networks of three-fold coordinated carbon atoms may result in a wide range of geometries. This has led to the postulation that structures such as the negatively curved schwarzites and tori may also be synthesized. In particular, theoretical calculations have shown the cohesive energy of schwarzites to be higher than that of C{sub 60}. Presented here is an analytical model describing the energetics of the most common sp{sup 2}-carbon single nanostructures as well as the hypothetical P-schwarzite. An expression for the energy with respect to a flat graphite sheet is written as the sum of a strain energy term (arising from curving of the carbon network) and a dangling bond energy term (not negligible in an inert environment). The relative stability of carbon spheres, tubes, planes and minimal surfaces is then investigated as a function of the dangling bond energy. In an inert atmosphere (large dangling bond energy), the cylinder appears to be the most stable geometry up to a certain size (about 40 atoms only). Above this number of atoms, the sphere is found to be energetically favoured. In a reactive environment, flat sheets are found to have the lowest energy, as expected. The other structures appeared to be always less stable than tubes, spheres and planes. However, small proportions of negatively curved sheets may occur at high temperatures. These results are compared with known experimental facts

  6. Platinum plasmonic nanostructure arrays for massively parallel single-molecule detection based on enhanced fluorescence measurements

    International Nuclear Information System (INIS)

    Saito, Toshiro; Takahashi, Satoshi; Obara, Takayuki; Itabashi, Naoshi; Imai, Kazumichi

    2011-01-01

    We fabricated platinum bowtie nanostructure arrays producing fluorescence enhancement and evaluated their performance using two-photon photoluminescence and single-molecule fluorescence measurements. A comprehensive selection of suitable materials was explored by electromagnetic simulation and Pt was chosen as the plasmonic material for visible light excitation near 500 nm, which is preferable for multicolor dye-labeling applications like DNA sequencing. The observation of bright photoluminescence (λ = 500-600 nm) from each Pt nanostructure, induced by irradiation at 800 nm with a femtosecond laser pulse, clearly indicates that a highly enhanced local field is created near the Pt nanostructure. The attachment of a single dye molecule was attempted between the Pt triangles of each nanostructure by using selective immobilization chemistry. The fluorescence intensities of the single dye molecule localized on the nanostructures were measured. A highly enhanced fluorescence, which was increased by a factor of 30, was observed. The two-photon photoluminescence intensity and fluorescence intensity showed qualitatively consistent gap size dependence. However, the average fluorescence enhancement factor was rather repressed even in the nanostructure with the smallest gap size compared to the large growth of photoluminescence. The variation of the position of the dye molecule attached to the nanostructure may influence the wide distribution of the fluorescence enhancement factor and cause the rather small average value of the fluorescence enhancement factor.

  7. Analysis of SSN 688 Class Submarine Maintenance Delays

    Science.gov (United States)

    2017-06-01

    Simplified Notional Submarine FRP (Independent Deployer) ..................11  Figure 8.  Evolution of Los Angeles Class Submarine Notional...Number TFP Technical Foundation Paper URO Unrestricted Operations xv ACKNOWLEDGMENTS I would like to thank my lead advisor, Professor Nick Dew...only on Los Angeles (SSN 688)-class submarines. Being the higher quantity and older generation submarine hull type, the Los Angeles class submarine

  8. Single-electron transport in graphene-like nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Kuei-Lin, E-mail: klc43@mit.edu [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Xu, Yang, E-mail: yangxu-isee@zju.edu.cn [Institute of Microelectronics and Optoelectronics, College of Information Science and Electronic Engineering, Zhejiang University, 310027 (China)

    2017-01-31

    Two-dimensional (2D) materials for their versatile band structures and strictly 2D nature have attracted considerable attention over the past decade. Graphene is a robust material for spintronics owing to its weak spin–orbit and hyperfine interactions, while monolayer transition metal dichalcogenides (TMDs) possess a Zeeman effect-like band splitting in which the spin and valley degrees of freedom are nondegenerate. The surface states of topological insulators (TIs) exhibit a spin–momentum locking that opens up the possibility of controlling the spin degree of freedom in the absence of an external magnetic field. Nanostructures made of these materials are also viable for use in quantum computing applications involving the superposition and entanglement of individual charge and spin quanta. In this article, we review a selection of transport studies addressing the confinement and manipulation of charges in nanostructures fabricated from various 2D materials. We supply the entry-level knowledge for this field by first introducing the fundamental properties of 2D bulk materials followed by the theoretical background relevant to the physics of nanostructures. Subsequently, a historical review of experimental development in this field is presented, from the early demonstration of graphene nanodevices on SiO{sub 2} substrate to more recent progress in utilizing hexagonal boron nitride to reduce substrate disorder. In the second part of this article, we extend our discussion to TMDs and TI nanostructures. We aim to outline the current challenges and suggest how future work will be geared towards developing spin qubits in 2D materials.

  9. Nanoscale and femtosecond optical autocorrelator based on a single plasmonic nanostructure

    International Nuclear Information System (INIS)

    Melentiev, P N; Afanasiev, A E; Balykin, V I; Tausenev, A V; Konyaschenko, A V; Klimov, V V

    2014-01-01

    We demonstrated a nanoscale size, ultrafast and multiorder optical autocorrelator with a single plasmonic nanostructure for measuring the spatio-temporal dynamics of femtosecond laser light. As a nanostructure, we use a split hole resonator (SHR), which was made in an aluminium nanofilm. The Al material yields the fastest response time (100 as). The SHR nanostructure ensures a high nonlinear optical efficiency of the interaction with laser radiation, which leads to (1) the second, (2) the third harmonics generation and (3) the multiphoton luminescence, which, in turn, are used to perform multi-order autocorrelation measurements. The nano-sized SHR makes it possible to conduct autocorrelation measurements (i) with a subwavelength spatial resolution and (ii) with no significant influence on the duration of the laser pulse. The time response realized by the SHR nanostructure is about 10 fs. (letter)

  10. Improved Space Surveillance Network (SSN) Scheduling using Artificial Intelligence Techniques

    Science.gov (United States)

    Stottler, D.

    There are close to 20,000 cataloged manmade objects in space, the large majority of which are not active, functioning satellites. These are tracked by phased array and mechanical radars and ground and space-based optical telescopes, collectively known as the Space Surveillance Network (SSN). A better SSN schedule of observations could, using exactly the same legacy sensor resources, improve space catalog accuracy through more complementary tracking, provide better responsiveness to real-time changes, better track small debris in low earth orbit (LEO) through efficient use of applicable sensors, efficiently track deep space (DS) frequent revisit objects, handle increased numbers of objects and new types of sensors, and take advantage of future improved communication and control to globally optimize the SSN schedule. We have developed a scheduling algorithm that takes as input the space catalog and the associated covariance matrices and produces a globally optimized schedule for each sensor site as to what objects to observe and when. This algorithm is able to schedule more observations with the same sensor resources and have those observations be more complementary, in terms of the precision with which each orbit metric is known, to produce a satellite observation schedule that, when executed, minimizes the covariances across the entire space object catalog. If used operationally, the results would be significantly increased accuracy of the space catalog with fewer lost objects with the same set of sensor resources. This approach inherently can also trade-off fewer high priority tasks against more lower-priority tasks, when there is benefit in doing so. Currently the project has completed a prototyping and feasibility study, using open source data on the SSN's sensors, that showed significant reduction in orbit metric covariances. The algorithm techniques and results will be discussed along with future directions for the research.

  11. Growth in the Number of SSN Tracked Orbital Objects

    Science.gov (United States)

    Stansbery, Eugene G.

    2004-01-01

    The number of objects in earth orbit tracked by the US Space Surveillance Network (SSN) has experienced unprecedented growth since March, 2003. Approximately 2000 orbiting objects have been added to the "Analyst list" of tracked objects. This growth is primarily due to the resumption of full power/full time operation of the AN/FPS-108 Cobra Dane radar located on Shemya Island, AK. Cobra Dane is an L-band (23-cm wavelength) phased array radar which first became operational in 1977. Cobra Dane was a "Collateral Sensor" in the SSN until 1994 when its communication link with the Space Control Center (SCC) was closed. NASA and the Air Force conducted tests in 1999 using Cobra Dane to detect and track small debris. These tests confirmed that the radar was capable of detecting and maintaining orbits on objects as small as 5-cm diameter. Subsequently, Cobra Dane was reconnected to the SSN and resumed full power/full time space surveillance operations on March 4, 2003. This paper will examine the new data and its implications to the understanding of the orbital debris environment and orbital safety.

  12. Evolution between self-assembled single and double ring-like nanostructures

    International Nuclear Information System (INIS)

    Lee, J H; Wang, Zh M; Abuwaar, Z Y; Strom, N W; Salamo, G J

    2006-01-01

    The evolution between lattice-matched GaAs/Al 0.3 Ga 0.7 As single and double ring-like nanostructures is studied, with an emphasis on the construction and destruction of the observed outer ring. Using droplet epitaxy, this was achieved by directly controlling the Ga surface diffusion on GaAs(100). Double ring-like nanostructures were observed at relatively low temperatures under a fixed As 4 flux (beam equivalent pressure (BEP) of 6.4 μTorr) and at a fixed temperature under a high As 4 flux. The construction of the outer ring can be controlled through surface diffusion by varying the substrate temperature or the As 4 flux. Single ring-like nanostructures were realized both at relatively high temperatures under a fixed As 4 flux, and at low temperatures under a relatively low As 4 flux

  13. Single-step rapid assembly of DNA origami nanostructures for addressable nanoscale bioreactors

    DEFF Research Database (Denmark)

    Fu, Yanming; Zeng, Dongdong; Chao, Jie

    2013-01-01

    nm resolution and at the single-molecule level. We attach a pair of enzymes (horseradish peroxidase and glucose oxidase) at the inner side of DNA nanotubes and observe high coupling efficiency of enzyme cascade within this confined nanospace. Hence, DNA nanostructures with such unprecedented...

  14. Thermal Conductivity in Nanostructured Films: From Single Cellulose Nanocrystals to Bulk Films

    Science.gov (United States)

    Jairo A. Diaz; Zhijiang Ye; Xiawa Wu; Arden L. Moore; Robert J. Moon; Ashlie Martini; Dylan J. Boday; Jeffrey P. Youngblood

    2014-01-01

    We achieved a multiscale description of the thermal conductivity of cellulose nanocrystals (CNCs) from single CNCs (~­0.72−5.7 W m−1 K−1) to their organized nanostructured films (~­0.22−0.53 W m−1 K−1) using...

  15. Top-down fabrication of plasmonic nanostructures for deterministic coupling to single quantum emitters

    NARCIS (Netherlands)

    Pfaff, W.; Vos, A.; Hanson, R.

    2013-01-01

    Metal nanostructures can be used to harvest and guide the emission of single photon emitters on-chip via surface plasmon polaritons. In order to develop and characterize photonic devices based on emitter-plasmon hybrid structures, a deterministic and scalable fabrication method for such structures

  16. ANALISIS KUALITAS PENGELOLAAN KELAS PEMBELAJARAN SAINS PADA SMP SSN DI KABUPATEN PATI

    Directory of Open Access Journals (Sweden)

    Prasetyaningsih Prasetyaningsih

    2016-12-01

    Full Text Available Abstract This study aimed at identifying in: (1 planning the classroom management for the SSN classes and (2 managing the classroom, in the teaching and learning process of science in SSN schools.This is a evaluatif study which focuses on the classroom management of science learning in SSN junior high schools. The subjects of the research are SSN Junior High Schools of Pati Regency which focuses on the classroom management of science learning. There are six SSN schools, namely  SMP N 2 Pati, SMP N 4 Pati,  SMP N 1 Wedarijaksa, SMP N 1 Trangkil, SMP N 1 Tlogowungu, and SMP N 1 Gabus. The data were gained through observation, interview, questionnaire, and document study.The result shows that : the classroom management planning  in SSN Junior High Schools in the science learning at Pati Regency are categorizes good: the science teacher  SSN Junior High School the use of ICT in science learning was not taken into account, teaching materials (handouts, worksheets, modules and ICT-based teaching material were not developed yet, the assessment planning did not complete. Process in the science learning at SNN junior High School are as categirizes good.  Keywords: Classroom Management, SSN, Science Learning. Abstrak Penelitian ini bertujuan untuk: (1 mengidentifikasi perencanaan pengelolaan kelas di SMP SSN dalam pembelajaran sains; (2 mengidentifikasi proses pengelolaan kelas di SMP SSN dalam pembelajaran sains. Penelitian ini merupakan penelitian evaluatif, yang memfokuskan pada kualitas pengelolaan kelas pembelajaran sains pada SMP SSN. Subjek penelitian ini SMP SSN Kabupaten Pati yang difokuskan pada perencanaan dan pelaksanaan pengelolaan kelas pembelajaran sains.Data penelitian diperoleh melalui: observasi, wawancara, angket, dan dokumentasi. Data yang diperoleh bersifat subjektif, berupa hasil observasi, wawancara, dan angket.Hasil penelitian menunjukkan: perencanaan pengelolaan kelas di SMP SSN dalam pembelajaran sains berkategori baik

  17. Solution growth of single crystal methylammonium lead halide perovskite nanostructures for optoelectronic and photovoltaic applications.

    Science.gov (United States)

    Fu, Yongping; Meng, Fei; Rowley, Matthew B; Thompson, Blaise J; Shearer, Melinda J; Ma, Dewei; Hamers, Robert J; Wright, John C; Jin, Song

    2015-05-06

    Understanding crystal growth and improving material quality is important for improving semiconductors for electronic, optoelectronic, and photovoltaic applications. Amidst the surging interest in solar cells based on hybrid organic-inorganic lead halide perovskites and the exciting progress in device performance, improved understanding and better control of the crystal growth of these perovskites could further boost their optoelectronic and photovoltaic performance. Here, we report new insights on the crystal growth of the perovskite materials, especially crystalline nanostructures. Specifically, single crystal nanowires, nanorods, and nanoplates of methylammonium lead halide perovskites (CH3NH3PbI3 and CH3NH3PbBr3) are successfully grown via a dissolution-recrystallization pathway in a solution synthesis from lead iodide (or lead acetate) films coated on substrates. These single crystal nanostructures display strong room-temperature photoluminescence and long carrier lifetime. We also report that a solid-liquid interfacial conversion reaction can create a highly crystalline, nanostructured MAPbI3 film with micrometer grain size and high surface coverage that enables photovoltaic devices with a power conversion efficiency of 10.6%. These results suggest that single-crystal perovskite nanostructures provide improved photophysical properties that are important for fundamental studies and future applications in nanoscale optoelectronic and photonic devices.

  18. Low-Power Photothermal Probing of Single Plasmonic Nanostructures with Nanomechanical String Resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Wu, Kaiyu; Larsen, Peter Emil

    2014-01-01

    We demonstrate the direct photothermal probing and mapping of single plasmonic nanostructures via the temperature-induced detuning of nanomechanical string resonators. Single Au nanoslits and nanorods are illuminated with a partially polarized focused laser beam (λ = 633 nm) with irradiances...... in the range of 0.26–38 μW/μm2. Photothermal heating maps with a resolution of ∼375 nm are obtained by scanning the laser over the nanostructures. Based on the string sensitivities, absorption efficiencies of 2.3 ± 0.3 and 1.1 ± 0.7 are extracted for a single nanoslit (53 nm × 1 μm) and nanorod (75 nm × 185 nm......). Our results show that nanomechanical resonators are a unique and robust analysis tool for the low-power investigation of thermoplasmonic effects in plasmonic hot spots....

  19. Sound Surfing Network (SSN): Mobile Phone-based Sound Spatialization with Audience Collaboration

    OpenAIRE

    Park, Saebyul; Ban, Seonghoon; Hong, Dae Ryong; Yeo, Woon Seung

    2013-01-01

    SSN (Sound Surfing Network) is a performance system that provides a new musicalexperience by incorporating mobile phone-based spatial sound control tocollaborative music performance. SSN enables both the performer and theaudience to manipulate the spatial distribution of sound using the smartphonesof the audience as distributed speaker system. Proposing a new perspective tothe social aspect music appreciation, SSN will provide a new possibility tomobile music performances in the context of in...

  20. Electrochemistry of single molecules and biomolecules, molecular scale nanostructures, and low-dimensional systems

    DEFF Research Database (Denmark)

    Nazmutdinov, Renat R.; Zinkicheva, Tamara T.; Zinkicheva, Tamara T.

    2018-01-01

    Electrochemistry at ultra-small scales, where even the single molecule or biomolecule can be characterized and manipulated, is on the way to a consolidated status. At the same time molecular electrochemistry is expanding into other areas of sophisticated nano- and molecular scale systems includin...... molecular scale metal and semiconductor nanoparticles (NPs) and other nanostructures, e.g. nanotubes, “nanoflowers” etc.. The new structures offer both new electronic properties and highly confined novel charge transfer environments....

  1. Single-electron tunneling in double-barrier nanostructures

    International Nuclear Information System (INIS)

    Goldman, V.J.; Su, B.; Cunningham, J.E.

    1992-01-01

    In this paper, the authors review experimental study of charge transport in nanometer double-barrier resonant tunneling devices. Heterostructure material is asymmetric: one barrier is substantially less transparent than the other. Resonant tunneling through size-quantized well states and single-electron charging of the well are thus largely separated in the two bias polarities. When the emitter barrier is more transparent than the collector barrier, electrons accumulate in the well; incremental electron occupation of the well is accompanied by Coulomb blockade leading to sharp steps of the tunneling current. When the emitter barrier is less transparent, the current reflects resonant tunneling of just one electron at a time through size-quantized well states; the current peaks and/or steps (depending on experimental parameters) appear in current-voltage characteristics. Magnetic field and temperature effects are also reviewed. Good agreement is achieved in comparison of many features of experimental data with simple theoretical models

  2. Method for making a single-step etch mask for 3D monolithic nanostructures

    International Nuclear Information System (INIS)

    Grishina, D A; Harteveld, C A M; Vos, W L; Woldering, L A

    2015-01-01

    Current nanostructure fabrication by etching is usually limited to planar structures as they are defined by a planar mask. The realization of three-dimensional (3D) nanostructures by etching requires technologies beyond planar masks. We present a method for fabricating a 3D mask that allows one to etch three-dimensional monolithic nanostructures using only CMOS-compatible processes. The mask is written in a hard-mask layer that is deposited on two adjacent inclined surfaces of a Si wafer. By projecting in a single step two different 2D patterns within one 3D mask on the two inclined surfaces, the mutual alignment between the patterns is ensured. Thereby after the mask pattern is defined, the etching of deep pores in two oblique directions yields a three-dimensional structure in Si. As a proof of concept we demonstrate 3D mask fabrication for three-dimensional diamond-like photonic band gap crystals in silicon. The fabricated crystals reveal a broad stop gap in optical reflectivity measurements. We propose how 3D nanostructures with five different Bravais lattices can be realized, namely cubic, tetragonal, orthorhombic, monoclinic and hexagonal, and demonstrate a mask for a 3D hexagonal crystal. We also demonstrate the mask for a diamond-structure crystal with a 3D array of cavities. In general, the 2D patterns on the different surfaces can be completely independently structured and still be in perfect mutual alignment. Indeed, we observe an alignment accuracy of better than 3.0 nm between the 2D mask patterns on the inclined surfaces, which permits one to etch well-defined monolithic 3D nanostructures. (paper)

  3. Facile conversion of bulk metal surface to metal oxide single-crystalline nanostructures by microwave irradiation: Formation of pure or Cr-doped hematite nanostructure arrays

    International Nuclear Information System (INIS)

    Cho, Seungho; Jeong, Haeyoon; Lee, Kun-Hong

    2010-01-01

    We report a method for converting the surfaces of bulk metal substrates (pure iron or stainless steel) to metal oxide (hematite or Cr-doped hematite) nanostructures using microwave irradiation. When microwave radiation (2.45 GHz, single-mode) was applied to a metal substrate under the flow of a gas mixture containing O 2 and Ar, metal oxide nanostructures formed and entirely covered the substrate. The nanostructures were single crystalline, and the atomic ratios of the substrate metals were preserved in the nanostructures. When a pure iron sheet was used as a substrate, hematite nanowires (1000 W microwave radiation) or nanosheets (1800 W microwave radiation) formed on the surface of the substrate. When a SUS410 sheet was used as a substrate, slightly curved rod-like nanostructures were synthesized. The oxidation states of Fe and Cr in these nanorods were Fe 3+ and Cr 3+ . Quantitative analyses revealed an average Fe/Cr atomic ratio of 9.2, nearly identical to the ratio of the metals in the SUS410 substrate.

  4. 75 FR 7546 - Foreign Trade Regulations (FTR): Eliminate the Social Security Number (SSN) as an Identification...

    Science.gov (United States)

    2010-02-22

    ... DEPARTMENT OF COMMERCE Census Bureau 15 CFR Part 30 [Docket Number: 090422707-91445-02] RIN 0607-AA48 Foreign Trade Regulations (FTR): Eliminate the Social Security Number (SSN) as an Identification... Trade Regulations (FTR) to eliminate the requirement to report a Social Security Number (SSN) as an...

  5. Quantitative and Isolated Measurement of Far-Field Light Scattering by a Single Nanostructure

    Science.gov (United States)

    Kim, Donghyeong; Jeong, Kwang-Yong; Kim, Jinhyung; Ee, Ho-Seok; Kang, Ju-Hyung; Park, Hong-Gyu; Seo, Min-Kyo

    2017-11-01

    Light scattering by nanostructures has facilitated research on various optical phenomena and applications by interfacing the near fields and free-propagating radiation. However, direct quantitative measurement of far-field scattering by a single nanostructure on the wavelength scale or less is highly challenging. Conventional back-focal-plane imaging covers only a limited solid angle determined by the numerical aperture of the objectives and suffers from optical aberration and distortion. Here, we present a quantitative measurement of the differential far-field scattering cross section of a single nanostructure over the full hemisphere. In goniometer-based far-field scanning with a high signal-to-noise ratio of approximately 27.4 dB, weak scattering signals are efficiently isolated and detected under total-internal-reflection illumination. Systematic measurements reveal that the total and differential scattering cross sections of a Au nanorod are determined by the plasmonic Fabry-Perot resonances and the phase-matching conditions to the free-propagating radiation, respectively. We believe that our angle-resolved far-field measurement scheme provides a way to investigate and evaluate the physical properties and performance of nano-optical materials and phenomena.

  6. Single Nanostructure Electrochemical Devices for Studying Electronic Properties and Structural Changes in Lithiated Si Nanowires

    KAUST Repository

    McDowell, Matthew T.; Cui, Yi

    2011-01-01

    Nanostructured Si is a promising anode material for the next generation of Li-ion batteries, but few studies have focused on the electrical properties of the Li-Si alloy phase, which are important for determining power capabilities and ensuring sufficient electrical conduction in the electrode structure. Here, we demonstrate an electrochemical device framework suitable for testing the electrical properties of single Si nanowires (NWs) at different lithiation states and correlating these properties with structural changes via transmission electron microscopy (TEM). We fi nd that single Si NWs usually exhibit Ohmic I - V response in the lithiated state, with conductivities two to three orders of magnitude higher than in the delithiated state. After a number of sequential lithiation/delithiation cycles, the single NWs show similar conductivity after each lithiation step but show large variations in conductivity in the delithiated state. Finally, devices with groups of NWs in physical contact were fabricated, and structural changes in the NWs were observed after lithiation to investigate how the electrical resistance of NW junctions and the NWs themselves affect the lithiation behavior. The results suggest that electrical resistance of NW junctions can limit lithiation. Overall, this study shows the importance of investigating the electronic properties of individual components of a battery electrode (single nanostructures in this case) along with studying the nature of interactions within a collection of these component structures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Single Nanostructure Electrochemical Devices for Studying Electronic Properties and Structural Changes in Lithiated Si Nanowires

    KAUST Repository

    McDowell, Matthew T.

    2011-07-19

    Nanostructured Si is a promising anode material for the next generation of Li-ion batteries, but few studies have focused on the electrical properties of the Li-Si alloy phase, which are important for determining power capabilities and ensuring sufficient electrical conduction in the electrode structure. Here, we demonstrate an electrochemical device framework suitable for testing the electrical properties of single Si nanowires (NWs) at different lithiation states and correlating these properties with structural changes via transmission electron microscopy (TEM). We fi nd that single Si NWs usually exhibit Ohmic I - V response in the lithiated state, with conductivities two to three orders of magnitude higher than in the delithiated state. After a number of sequential lithiation/delithiation cycles, the single NWs show similar conductivity after each lithiation step but show large variations in conductivity in the delithiated state. Finally, devices with groups of NWs in physical contact were fabricated, and structural changes in the NWs were observed after lithiation to investigate how the electrical resistance of NW junctions and the NWs themselves affect the lithiation behavior. The results suggest that electrical resistance of NW junctions can limit lithiation. Overall, this study shows the importance of investigating the electronic properties of individual components of a battery electrode (single nanostructures in this case) along with studying the nature of interactions within a collection of these component structures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Digitally encoded DNA nanostructures for multiplexed, single-molecule protein sensing with nanopores

    Science.gov (United States)

    Bell, Nicholas A. W.; Keyser, Ulrich F.

    2016-07-01

    The simultaneous detection of a large number of different analytes is important in bionanotechnology research and in diagnostic applications. Nanopore sensing is an attractive method in this regard as the approach can be integrated into small, portable device architectures, and there is significant potential for detecting multiple sub-populations in a sample. Here, we show that highly multiplexed sensing of single molecules can be achieved with solid-state nanopores by using digitally encoded DNA nanostructures. Based on the principles of DNA origami, we designed a library of DNA nanostructures in which each member contains a unique barcode; each bit in the barcode is signalled by the presence or absence of multiple DNA dumbbell hairpins. We show that a 3-bit barcode can be assigned with 94% accuracy by electrophoretically driving the DNA structures through a solid-state nanopore. Select members of the library were then functionalized to detect a single, specific antibody through antigen presentation at designed positions on the DNA. This allows us to simultaneously detect four different antibodies of the same isotype at nanomolar concentration levels.

  9. Fabrication of single-crystalline plasmonic nanostructures on transparent and flexible amorphous substrates

    Science.gov (United States)

    Mori, Tomohiro; Mori, Takeshi; Tanaka, Yasuhiro; Suzaki, Yoshifumi; Yamaguchi, Kenzo

    2017-02-01

    A new experimental technique is developed for producing a high-performance single-crystalline Ag nanostructure on transparent and flexible amorphous substrates for use in plasmonic sensors and circuit components. This technique is based on the epitaxial growth of Ag on a (001)-oriented single-crystalline NaCl substrate, which is subsequently dissolved in ultrapure water to allow the Ag film to be transferred onto a wide range of different substrates. Focused ion beam milling is then used to create an Ag nanoarray structure consisting of 200 cuboid nanoparticles with a side length of 160 nm and sharp, precise edges. This array exhibits a strong signal and a sharp peak in plasmonic properties and Raman intensity when compared with a polycrystalline Ag nanoarray.

  10. Evolution of the zinc compound nanostructures in zinc acetate single-source solution

    International Nuclear Information System (INIS)

    Wang Ying; Li Yinhua; Zhou Zhengzhi; Zu Xihong; Deng Yulin

    2011-01-01

    A series of nanostructured zinc compounds with different nanostructures such as nanobelts, flake-like, flower-like, and twinning crystals was synthesized using zinc acetate (Zn(Ac) 2 ) as a single-source. The evolution of the zinc compounds from layered basic zinc acetate (LBZA) to bilayered basic zinc acetate (BLBZA) and twinned ZnO nano/microcrystal was studied. The low-angle X-ray diffraction spectra indicate the layered spacing is 1.34 and 2.1 nm for LBZA and BLBZA, respectively. The Fourier transform infrared (FTIR) spectra results confirmed that the bonding force of acetate anion with zinc cations decreases with the phase transformation from Zn(Ac) 2 to BLBZA, and finally to LBZA. The OH − groups gradually replaced the acetate groups coordinated to the matrix zinc cation, and the acetate groups were released completely. Finally, the Zn(OH) 2 and ZnO were formed at high temperature. The conversion process from Zn(Ac) 2 to ZnO with release of acetate anions can be described as Zn(Ac) 2 → BLBZA → LBZA → Zn(OH) 2 → ZnO.

  11. Optical trapping and Raman spectroscopy of single nanostructures using standing-wave Raman tweezers

    Science.gov (United States)

    Wu, Mu-ying; He, Lin; Chen, Gui-hua; Yang, Guang; Li, Yong-qing

    2017-08-01

    Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped micro-particle, but is generally less effective for individual nano-sized objects in the 10-100 nm range. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap (SWOT) with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus is more stable and sensitive in measuring nanoparticles in liquid with 4-8 fold increase in the Raman signals. It can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, polystyrene beads (100 nm), SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles with a low laser power of a few milliwatts. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.

  12. Controlled nanostructure and high loading of single-walled carbon nanotubes reinforced polycarbonate composite

    International Nuclear Information System (INIS)

    Wang Shiren; Liang Zhiyong; Pham, Giang; Park, Young-Bin; Wang, Ben; Zhang, Chuck; Kramer, Leslie; Funchess, Percy

    2007-01-01

    This paper presents an effective technique to fabricate thermoplastic nanocomposites with high loading of well-dispersed single-walled carbon nanotubes (SWNTs). SWNT membranes were made from a multi-step dispersion and filtration method, and then impregnated with polycarbonate solution to make thermoplastic nanocomposites. High loading of nanotubes was achieved by controlling the viscosity of polycarbonate solution. SEM and AFM characterization results revealed the controlled nanostructure in the resultant nanocomposites. Dynamic mechanical property tests indicated that the storage modulus of the resulting nanocomposites at 20 wt% nanotubes loading was improved by a factor of 3.4 compared with neat polycarbonate material. These results suggest the developed approach is an effective way to fabricate thermoplastic nanocomposites with good dispersion and high SWNT loading

  13. Morphology-controlled synthesis of ZnS nanostructures via single-source approaches

    International Nuclear Information System (INIS)

    Han, Qiaofeng; Qiang, Fei; Wang, Meijuan; Zhu, Junwu; Lu, Lude; Wang, Xin

    2010-01-01

    ZnS nanoparticles of various morphologies, including hollow or solid spherical, and polyhedral shape, were synthesized from single-source precursor Zn(S 2 COC 2 H 5 ) 2 without using a surfactant or template. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy. The results indicate that ZnS hollow and solid spheres assembled by nanoparticles can be easily generated by the solution phase thermalysis of Zn(S 2 COC 2 H 5 ) 2 at 80 o C using N, N-dimethylformamide (DMF) and ethylene glycol (EG) or water as solvents, respectively, whereas solvothermal process of the same precursor led to ZnS nanoparticles of polyhedral shape with an average size of 120 nm. The optical properties of these ZnS nanostructures were investigated by room-temperature luminescence and UV-vis diffuse reflectance spectra.

  14. Biomimetic plasmonic color generated by the single-layer coaxial honeycomb nanostructure arrays

    Science.gov (United States)

    Zhao, Jiancun; Gao, Bo; Li, Haoyong; Yu, Xiaochang; Yang, Xiaoming; Yu, Yiting

    2017-07-01

    We proposed a periodic coaxial honeycomb nanostructure array patterned in a silver film to realize the plasmonic structural color, which was inspired from natural honeybee hives. The spectral characteristics of the structure with variant geometrical parameters are investigated by employing a finite-difference time-domain method, and the corresponding colors are thus derived by calculating XYZ tristimulus values corresponding with the transmission spectra. The study demonstrates that the suggested structure with only a single layer has high transmission, narrow full-width at half-maximum, and wide color tunability by changing geometrical parameters. Therefore, the plasmonic colors realized possess a high color brightness, saturation, as well as a wide color gamut. In addition, the strong polarization independence makes it more attractive for practical applications. These results indicate that the recommended color-generating plasmonic structure has various potential applications in highly integrated optoelectronic devices, such as color filters and high-definition displays.

  15. Probabilistic risk assessment (PRA) on the effectiveness of a core rescue system (SSN) for PWRs

    International Nuclear Information System (INIS)

    Petrangeli, G.; Valeri, A.

    1983-01-01

    Safety systems for the prevention of LWR core severe damage have recently been studied, which are based on automatic primary system depressurization and on borated water injection by low pressure accumulators. These systems have been named Core Rescue System (SSN). The present study evaluates the reduction in core melt probability brought about by the installation of a SSN system on the RSS (WASH 1400) PWR plant (Surry 1). The calculated result is a core melt probability reduction factor of about 250. Taking into account the possible effect of external or internal unknown events of negligible, yet undefined, probability it is concluded that a SSN system can make a plant ten times safer. The first part of a review report by Prof. N.C.Rasmussen, MIT, dealing with general comment, is attached

  16. MINAT SISWA SMP N RSBI DAN SSN DI KOTA SEMARANG DALAM MEMILIH SMK

    Directory of Open Access Journals (Sweden)

    Jarot Tri Bowo Santoso

    2016-01-01

    Full Text Available The objective of this study is to know junior high school students interest in choosing vocational school (SMK. The research took place in 2 RSBI junior high schools and 2 SSN junior high schools in Semarang. The population of this study 854 students and the samples were 120 students.The data were collected by questionnaire and interview. Then, the data were analyzed by percentage description. The results showed that (1 RSBI junior high school students interest in choosing vocational school is very low. (2 SSN junior high school students interest in choosing vocational school is very low.

  17. Method to make a single-step etch mask for 3D monolithic nanostructures

    NARCIS (Netherlands)

    Grishina, Diana; Harteveld, Cornelis A.M.; Woldering, L.A.; Vos, Willem L.

    2015-01-01

    Current nanostructure fabrication by etching is usually limited to planar structures as they are defined by a planar mask. The realization of three-dimensional (3D) nanostructures by etching requires technologies beyond planar masks. We present a method for fabricating a 3D mask that allows one to

  18. Towards IoT platforms’ integration : Semantic Translations between W3C SSN and ETSI SAREF

    NARCIS (Netherlands)

    Moreira, João Luiz; Daniele, L.M.; Ferreira Pires, Luis; van Sinderen, Marten J.; Wasielewska, Katarzyna; Szmeja, Pawel; Pawlowski, Wieslaw; Ganzha, Maria; Paprzycki, Marcin

    2017-01-01

    Several IoT ontologies have been developed lately to improve the semantic interoperability of IoT solutions. The most popular of these ontologies, the W3C Semantic Sensor Network (SSN), is considered an ontological foundation for diverse IoT initiatives, particularly OpenIoT. With characteristics

  19. 78 FR 9765 - Assigning New Social Security Numbers (SSN) for Children Age 13 and Under

    Science.gov (United States)

    2013-02-11

    ..., during regular business hours, by arranging with the contact person identified below. FOR FURTHER...) and private businesses (such as banks and credit reporting companies), when we assign a new SSN, these... an individual with a work history, a driving record, and a credit history. Under the policy we are...

  20. Molecular Processes Studied at a Single-Molecule Level Using DNA Origami Nanostructures and Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Ilko Bald

    2014-09-01

    Full Text Available DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates.

  1. A Plan to Optimize the Management of Weld ID SSN Numbering System for Nuclear Power Plants in Korea

    International Nuclear Information System (INIS)

    Yoo, Hyun Ju; Cho, Chan Hee; Kim, Jin Hoi; Park, Dong Min

    2016-01-01

    Summary Sheet Number(SSN) in the current LTP is an ID which means a weldment in a nuclear power plant. However, the SSN ID, which is unique on in a nuclear power plant, is not unique one if the weldments of entire nuclear power plant in Korea are treated in one system. Therefore, it is hard to manage the data during life time using the existing SSN ID system. It is also hard to configure the characteristics of weldment in mind because IDs implying Alloy600 and overlay weld do not exist in the existing SSN ID System. An optimized SSN numbering system managing weldments for the life time is introduced in this paper. Moreover, it is explained how to manage the SSN numbering system in the computer program system, too. The problem, which the weld is not harmoniously managed, would be solved provided adapting the new SSN ID introduced in this paper. A weld is managed during its life time from creation to extinction. The inquiry of inspection history of a concerned weld and the reference of statistics would be performed easily and rightly because the concerned weld can be accessed from anywhere connected to KHNP network such as KHNP headquater, plants and CRI

  2. Assembling three-dimensional nanostructures on metal surfaces with a reversible vertical single-atom manipulation: A theoretical modeling

    International Nuclear Information System (INIS)

    Yang Tianxing; Ye Xiang; Huang Lei; Xie Yiqun; Ke Sanhuang

    2012-01-01

    Highlights: ► We simulate the reversible vertical single-atom manipulations on several metal surfaces. ► We propose a method to predict whether a reversible vertical single-atom manipulation can be successful on several metal surfaces. ► A 3-dimensional Ni nanocluster is assembled on the Ni(1 1 1) surface using a Ni trimer-apex tip. - Abstract: We propose a theoretical model to show that pulling up an adatom from an atomic step requires a weaker force than from the flat surfaces of Al(0 0 1), Ni(1 1 1), Pt(1 1 0) and Au(1 1 0). Single adatom in the atomic step can be extracted vertically by a trimer-apex tip while can be released to the flat surface. This reversible vertical manipulation can then be used to fabricate a supported three-dimensional (3D) nanostructure on the Ni(1 1 1) surface. The present modeling can be used to predict whether the reversible vertical single-atom manipulation and thus the assembling of 3D nanostructures can be achieved on a metal surface.

  3. Vertically integrated (Ga, In)N nanostructures for future single photon emitters operating in the telecommunication wavelength range

    International Nuclear Information System (INIS)

    Winden, A; Mikulics, M; Grützmacher, D; Hardtdegen, H

    2013-01-01

    Important technological steps are discussed and realized for future room-temperature operation of III-nitride single photon emitters. First, the growth technology of positioned single pyramidal InN nanostructures capped by Mg-doped GaN is presented. The optimization of their optical characteristics towards narrowband emission in the telecommunication wavelength range is demonstrated. In addition, a device concept and technology was developed so that the nanostructures became singularly addressable. It was found that the nanopyramids emit in the telecommunication wavelength range if their size is chosen appropriately. A p-GaN contacting layer was successfully produced as a cap to the InN pyramids and the top p-contact was achievable using an intrinsically conductive polymer PEDOT:PSS, allowing a 25% increase in light transmittance compared to standard Ni/Au contact technology. Single nanopyramids were successfully integrated into a high-frequency device layout. These decisive technology steps provide a promising route to electrically driven and room-temperature operating InN based single photon emitters in the telecommunication wavelength range. (paper)

  4. Single attosecond pulse generation by using plasmon-driven double optical gating technology in crossed metal nanostructures

    Science.gov (United States)

    Feng, Liqiang; Liu, Katheryn

    2018-05-01

    An effective method to obtain the single attosecond pulses (SAPs) by using the multi-cycle plasmon-driven double optical gating (DOG) technology in the specifically designed metal nanostructures has been proposed and investigated. It is found that with the introduction of the crossed metal nanostructures along the driven and the gating polarization directions, not only the harmonic cutoff can be extended, but also the efficient high-order harmonic generation (HHG) at the very highest orders occurs only at one side of the region inside the nanostructure. As a result, a 93 eV supercontinuum with the near stable phase can be found. Further, by properly introducing an ultraviolet (UV) pulse into the driven laser polarization direction (which is defined as the DOG), the harmonic yield can be enhanced by two orders of magnitude in comparison with the singe polarization gating (PG) technology. However, as the polarized angle or the ellipticity of the UV pulse increase, the enhancement of the harmonic yield is slightly reduced. Finally, by superposing the selected harmonics from the DOG scheme, a 30 as SAP with intensity enhancement of two orders of magnitude can be obtained.

  5. Systematic Investigation of Controlled Nanostructuring of Mn 12 Single-Molecule Magnets Templated by Metal–Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Aulakh, Darpandeep [Department of Chemistry; amp, Biomolecular Science, Clarkson University, Potsdam, New York 13699, United States; Xie, Haomiao [Department of Chemistry, Texas A& amp,M University, College Station, Texas 77845, United States; Shen, Zhe [Department of Chemistry, Texas A& amp,M University, College Station, Texas 77845, United States; Harley, Alexander [Department of Chemistry; amp, Biomolecular Science, Clarkson University, Potsdam, New York 13699, United States; Zhang, Xuan [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States; Yakovenko, Andrey A. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States; Dunbar, Kim R. [Department of Chemistry, Texas A& amp,M University, College Station, Texas 77845, United States; Wriedt, Mario [Department of Chemistry; amp, Biomolecular Science, Clarkson University, Potsdam, New York 13699, United States

    2017-05-25

    This is the first systematic study exploring metal–organic frameworks (MOFs) as platforms for the controlled nanostructuring of molecular magnets. We report the incorporation of seven single-molecule magnets (SMMs) of general composition [Mn12O12(O2CR)16(OH2)4], with R = CF3 (1), (CH3)CCH2 (2), CH2Cl (3), CH2Br (4), CHCl2 (5), CH2But (6), and C6H5 (7), into the hexagonal channel pores of a mesoporous MOF host. The resulting nanostructured composites combine the key SMM properties with the functional properties of the MOF. Synchrotron-based powder diffraction with difference envelope density analysis, physisorption analysis (surface area and pore size distribution), and thermal analyses reveal that the well-ordered hexagonal structure of the host framework is preserved, and magnetic measurements indicate that slow relaxation of the magnetization, characteristic of the corresponding Mn12 derivative guests, occurs inside the MOF pores. Structural host–guest correlations including the bulkiness and polarity of peripheral SMM ligands are discussed as fundamental parameters influencing the global SMM@MOF loading capacities. These results demonstrate that employing MOFs as platforms for the nanostructuration of SMMs is not limited to a particular host–guest system but potentially applicable to a multitude of other molecular magnets. Such fundamental findings will assist in paving the way for the development of novel advanced spintronic devices.

  6. Facile and green fabrication of organic single-crystal hollow micro/nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jun; Chen Yingzhi; Ou Xuemei; Zhang Xiaohong [Nano-organic Photoelectronic Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Xiujuan, E-mail: xjzhang@suda.edu.cn, E-mail: xhzhang@mail.ipc.ac.cn [Functional Nano and Soft Materials Laboratory (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2011-07-15

    Under high humidity and appropriate temperature, tris (8-hydroxyquinoline) aluminum (Alq3) solid micro/nanostructures may be etched into hollow structures and still retain their crystalline structures and surface morphologies. The shapes and sizes of the hollow structures are easily adjusted by varying the experimental parameters. Throughout the entire process, water is introduced into the system instead of organic or corrosive solvents, making this method convenient and environmentally friendly; it can also be extended to application in other materials such as TCNQ.

  7. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. © 2011 IOP Publishing Ltd

  8. Tailoring the optical constants in single-crystal silicon with embedded silver nanostructures for advanced silicon photonics applications

    International Nuclear Information System (INIS)

    Akhter, Perveen; Huang, Mengbing; Spratt, William; Kadakia, Nirag; Amir, Faisal

    2015-01-01

    Plasmonic effects associated with metal nanostructures are expected to hold the key to tailoring light emission/propagation and harvesting solar energy in materials including single crystal silicon which remains the backbone in the microelectronics and photovoltaics industries but unfortunately, lacks many functionalities needed for construction of advanced photonic and optoelectronics devices. Currently, silicon plasmonic structures are practically possible only in the configuration with metal nanoparticles or thin film arrays on a silicon surface. This does not enable one to exploit the full potential of plasmonics for optical engineering in silicon, because the plasmonic effects are dominant over a length of ∼50 nm, and the active device region typically lies below the surface much beyond this range. Here, we report on a novel method for the formation of silver nanoparticles embedded within a silicon crystal through metal gettering from a silver thin film deposited at the surface to nanocavities within the Si created by hydrogen ion implantation. The refractive index of the Ag-nanostructured layer is found to be 3–10% lower or higher than that of silicon for wavelengths below or beyond ∼815–900 nm, respectively. Around this wavelength range, the optical extinction values increase by a factor of 10–100 as opposed to the pure silicon case. Increasing the amount of gettered silver leads to an increased extinction as well as a redshift in wavelength position for the resonance. This resonance is attributed to the surface plasmon excitation of the resultant silver nanoparticles in silicon. Additionally, we show that the profiles for optical constants in silicon can be tailored by varying the position and number of nanocavity layers. Such silicon crystals with embedded metal nanostructures would offer novel functional base structures for applications in silicon photonics, optoelectronics, photovoltaics, and plasmonics

  9. Nanostructuring on zinc phthalocyanine thin films for single-junction organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, Dhirendra K.; Kumar, Lokendra, E-mail: lokendrakr@allduniv.ac.in [Department of Physics, University of Allahabad, Allahabad-211 002 (India)

    2016-05-23

    Vertically aligned and random oriented crystalline molecular nanorods of organic semiconducting Zinc Phthalocyanine (ZnPc) have been grown on ITO coated glass substrate using solvent volatilization method. Interesting changes in surface morphology were observed under different solvent treatment. Vertically aligned nanorods of ZnPc thin film were observed in the films treated with acetone, where as the random oriented nanorods were observed in the films treated with chloroform. The X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) have been used for characterization of nanostructures. The optical properties of the nanorods have been investigated by UV-Vis. absorption spectroscopy.

  10. Photoluminescence quenching, structures, and photovoltaic properties of ZnO nanostructures decorated plasma grown single walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aïssa, Brahim, E-mail: brahim.aissa@mpbc.ca [University of Quebec, Centre Énergie, Matériaux et Télécommunications, INRS-EMT (Canada); Nedil, Mourad [Telebec Wireless Underground Communication Laboratory, UQAT (Canada); Belaidi, Abdelhak; Isaifan, Rima J. [Hamad Bin Khalifa University, Qatar Foundation, Qatar Environment and Energy Research Institute (Qatar); Bentouaf, Ali [University Hassiba Ben Bouali, Physics Department, Faculty of Science (Algeria); Fauteux, Christian; Therriault, Daniel [École Polytechnique de Montréal, Laboratory for Multiscale Mechanics (LM2), Mechanical Engineering Department (Canada)

    2017-05-15

    Zinc oxide (ZnO) nanostructures were successfully grown directly on single walled carbon nanotubes (SWCNT) template through the CO{sub 2} laser-induced chemical liquid deposition (LCLD) process. Photoluminescence (PL) of the deposited ZnO/SWCNT hybrid composites exhibits, at room temperature, a narrow near UV band located at 390 nm with no emission bands in the visible region, indicating a high degree of crystalline quality of the ZnO nanostructures. Moreover, when the relative SWCNT loads are varied within the composites, the PL intensity and the diffused optical reflectance diminish in comparison with those of ZnO alone, owing to the transfer of photo-excited electrons from ZnO to the SWCNT, and the enhancement of the optical absorbance, respectively. Finally, these ZnO/SWCNT hybrid composites are integrated into a heterojunction photovoltaic-based device, using PEDOT:PSS on ITO/glass substrate. The devices show an evident p–n junction behavior in the dark, and a clear I–V curve shift downward when illuminated with an open-circuit voltage of 1.1 V, a short circuit current density of 14.05 μA cm{sup −2}, and a fill factor of ∼35%. These results indicate that these composites fabricated via LCLD process could be promising for optoelectronic and energy-harvesting devices.

  11. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    Science.gov (United States)

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye.; van Oene, Maarten M.; Solano, Belen; Dekker, Nynke H.

    2016-05-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile

  12. Block copolymer systems: from single chain to self-assembled nanostructures.

    Science.gov (United States)

    Giacomelli, Cristiano; Schmidt, Vanessa; Aissou, Karim; Borsali, Redouane

    2010-10-19

    Recent advances in the field of macromolecular engineering applied to the fabrication of nanostructured materials using block copolymer chains as elementary building blocks are described in this feature article. By highlighting some of our work in the area and accounting for the contribution of other groups, we discuss the relationship between the physical-chemical properties of copolymer chains and the characteristics of nano-objects originating from their self-assembly in solution and in bulk, with emphasis on convenient strategies that allow for the control of composition, functionality, and topology at different levels of sophistication. In the case of micellar nanoparticles in solution, in particular, we present approaches leading to morphology selection via macromolecular architectural design, the functionalization of external solvent-philic shells with biomolecules (polysaccharides and proteins), and the maximization of micelle loading capacity by the suitable choice of solvent-phobic polymer segments. The fabrication of nanomaterials mediated by thin block copolymer films is also discussed. In this case, we emphasize the development of novel polymer chain manipulation strategies that ultimately allow for the preparation of precisely positioned nanodomains with a reduced number of defects via block-selective chemical reactivity. The challenges facing the soft matter community, the urgent demand to convert huge public and private investments into consumer products, and future possible directions in the field are also considered herein.

  13. Synthesis of anisotropic CdS nanostructures via a single-source route

    CSIR Research Space (South Africa)

    Rajasekhar Pullabhotla, VSR

    2011-02-01

    Full Text Available A cadmium tetrahydroisoquinoline dithiocarbamate (DTC) complex has been used as single-source precursor for the synthesis of highly faceted hexadecylamine (HDA) capped CdS nanoparticles. Hexagonal and close to cubic shaped particles with distinct...

  14. Vertical Alignment of Single-Walled Carbon Nanotubes on Nanostructure Fabricated by Atomic Force Microscope

    National Research Council Canada - National Science Library

    Lee, Haiwon

    2007-01-01

    This project focused on the behavior of single-wall carbon nanotubes (SWCNTs) in the electrophoresis cells and aligned growth of SWCNTs by thermal chemical vapor deposition on selectively deposited metallic nanoparticle...

  15. A Hydrological Sensor Web Ontology Based on the SSN Ontology: A Case Study for a Flood

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2017-12-01

    Full Text Available Accompanying the continuous development of sensor network technology, sensors worldwide are constantly producing observation data. However, the sensors and their data from different observation platforms are sometimes difficult to use collaboratively in response to natural disasters such as floods for the lack of semantics. In this paper, a hydrological sensor web ontology based on SSN ontology is proposed to describe the heterogeneous hydrological sensor web resources by importing the time and space ontology, instantiating the hydrological classes, and establishing reasoning rules. This work has been validated by semantic querying and knowledge acquiring experiments. The results demonstrate the feasibility and effectiveness of the proposed ontology and its potential to grow into a more comprehensive ontology for hydrological monitoring collaboratively. In addition, this method of ontology modeling is generally applicable to other applications and domains.

  16. Nanostructured current-confined single quantum dot light-emitting diode at 1300 nm

    NARCIS (Netherlands)

    Monat, C.; Alloing, B.; Zinoni, C.; Li, L.; Fiore, A.

    2006-01-01

    A novel light-emitting-diode structure is demonstrated, which relies on nanoscale current injection through an oxide aperture to achieve selective excitation of single InAs/GaAs quantum dots. Low-temp. electroluminescence spectra evidence discrete narrow lines around 1300 nm (line width ~ 75 micro

  17. Facile fabrication of single-crystal-diamond nanostructures with ultrahigh aspect ratio.

    OpenAIRE

    Tao Ye; Degen Christian

    2013-01-01

    A robust and facile approach for making single crystal diamond MEMS and NEMS devices is presented. The approach relies entirely on commercial diamond material and standard cleanroom processes. As an example batch fabrication of cantilever beams of thickness down to 45 nm and aspect ratios exceeding 2000:1 is demonstrated.

  18. Detection of a single synthetic antiferromagnetic nanoparticle with an AMR nanostructure: Comparison between simulations and experiments

    DEFF Research Database (Denmark)

    Donolato, M.; Gobbi, M.; Cantoni, M.

    2010-01-01

    magnetoresistance effect and hence an electrical signal. In this paper we use micromagnetic simulations to calculate the output signal of a particularly shaped device in the presence of a single synthetic antiferromagnetic nanoparticle. The calculated magnetoresistive signal is in good agreement with corresponding...

  19. A single-stranded architecture for cotranscriptional folding of RNA nanostructures

    DEFF Research Database (Denmark)

    Geary, Cody; Rothemund, Paul; Andersen, Ebbe Sloth

    2014-01-01

    Artificial DNA and RNA structures have been used as scaffolds for a variety of nanoscale devices. In comparison to DNA structures, RNA structures have been limited in size, but they also have advantages: RNA can fold during transcription and thus can be genetically encoded and expressed in cells....... We introduce an architecture for designing artificial RNA structures that fold from a single strand, in which arrays of antiparallel RNA helices are precisely organized by RNA tertiary motifs and a new type of crossover pattern. We constructed RNA tiles that assemble into hexagonal lattices...

  20. Single-step fabrication of electrodes with controlled nanostructured surface roughness using optically-induced electrodeposition

    Science.gov (United States)

    Liu, N.; Li, M.; Liu, L.; Yang, Y.; Mai, J.; Pu, H.; Sun, Y.; Li, W. J.

    2018-02-01

    The customized fabrication of microelectrodes from gold nanoparticles (AuNPs) has attracted much attention due to their numerous applications in chemistry and biomedical engineering, such as for surface-enhanced Raman spectroscopy (SERS) and as catalyst sites for electrochemistry. Herein, we present a novel optically-induced electrodeposition (OED) method for rapidly fabricating gold electrodes which are also surface-modified with nanoparticles in one single step. The electrodeposition mechanism, with respect to the applied AC voltage signal and the elapsed deposition time, on the resulting morphology and particle sizes was investigated. The results from SEM and AFM analysis demonstrated that 80-200 nm gold particles can be formed on the surface of the gold electrodes. Simultaneously, both the size of the nanoparticles and the roughness of the fabricated electrodes can be regulated by the deposition time. Compared to state-of-the-art methods for fabricating microelectrodes with AuNPs, such as nano-seed-mediated growth and conventional electrodeposition, this OED technique has several advantages including: (1) electrode fabrication and surface modification using nanoparticles are completed in a single step, eliminating the need for prefabricating micro electrodes; (2) the patterning of electrodes is defined using a digitally-customized, projected optical image rather than using fixed physical masks; and (3) both the fabrication and surface modification processes are rapid, and the entire fabrication process only requires less than 6 s.

  1. Characterization of nanostructures in the live cell plasma membrane utilizing advanced single molecule fluorescence techniques

    International Nuclear Information System (INIS)

    Brameshuber, M.

    2009-01-01

    Unrevealing the detailed structure of the cellular plasma membrane at a nanoscopic length scale is the key for understanding the regulation of various signaling pathways or interaction mechanism. Hypotheses postulate the existence of nanoscopic lipid platforms in the cell membrane which are termed lipid- or membrane rafts. Based on biochemical studies, rafts are believed to play a crucial role in many signaling processes. However, there is currently not much information on their size, shape, stability, surface density, composition and heterogeneity. In this thesis I present an ultra-sensitive fluorescence based method which allows for the first time the direct imaging of single mobile rafts in the live cell plasma membrane. The method senses rafts by their property to assemble a characteristic set of fluorescent marker-proteins or lipids on a time-scale of seconds. A special photobleaching protocol was developed and used to reduce the surface density of labeled mobile rafts down to the level of well-isolated diffraction-limited spots, without altering the single spot brightness. The statistical distribution of probe molecules per raft was determined by single molecule brightness analysis. For demonstration, I used the consensus markers Bodipy-GM1, a fluorescent lipid analogue, and glycosylphosphatidyl-inositol-anchored monomeric GFP. For both markers I found cholesterol-dependent association in the plasma membrane of living CHO and Jurkat T cells in the resting state, indicating the presence of mobile, stable rafts hosting these probes. I further characterized these structures by taking cell-to-cell variations under consideration. By comparing Bodipy-GM1 with mGFP-GPI homo-association upon temperature variation, two different states - a non-equilibrated and an equilibrated state - could be identified. I conclude that rafts are loaded non-randomly; the characteristic load is maintained during its lifetime in the plasma membrane of a non-activated cell. Beside these

  2. Morphological evolution of porous nanostructures grown from a single isolated anodic alumina nanochannel

    Science.gov (United States)

    Chen, Shih-Yung; Chang, Hsuan-Hao; Lai, Ming-Yu; Liu, Chih-Yi; Wang, Yuh-Lin

    2011-09-01

    Porous anodic aluminum oxide (AAO) membranes have been widely used as templates for growing nanomaterials because of their ordered nanochannel arrays with high aspect ratio and uniform pore diameter. However, the intrinsic growth behavior of an individual AAO nanochannel has never been carefully studied for the lack of a means to fabricate a single isolated anodic alumina nanochannel (SIAAN). In this study, we develop a lithographic method for fabricating a SIAAN, which grows into a porous hemispherical structure with its pores exhibiting fascinating morphological evolution during anodization. We also discover that the mechanical stress affects the growth rate and pore morphology of AAO porous structures. This study helps reveal the growth mechanism of arrayed AAO nanochannels grown on a flat aluminum surface and provides insights to help pave the way to altering the geometry of nanochannels on AAO templates for the fabrication of advanced nanocomposite materials.

  3. Morphological evolution of porous nanostructures grown from a single isolated anodic alumina nanochannel

    International Nuclear Information System (INIS)

    Chen, Shih-Yung; Wang, Yuh-Lin; Chang, Hsuan-Hao; Lai, Ming-Yu; Liu, Chih-Yi

    2011-01-01

    Porous anodic aluminum oxide (AAO) membranes have been widely used as templates for growing nanomaterials because of their ordered nanochannel arrays with high aspect ratio and uniform pore diameter. However, the intrinsic growth behavior of an individual AAO nanochannel has never been carefully studied for the lack of a means to fabricate a single isolated anodic alumina nanochannel (SIAAN). In this study, we develop a lithographic method for fabricating a SIAAN, which grows into a porous hemispherical structure with its pores exhibiting fascinating morphological evolution during anodization. We also discover that the mechanical stress affects the growth rate and pore morphology of AAO porous structures. This study helps reveal the growth mechanism of arrayed AAO nanochannels grown on a flat aluminum surface and provides insights to help pave the way to altering the geometry of nanochannels on AAO templates for the fabrication of advanced nanocomposite materials.

  4. Exploring Nanostructure Arrays for Single-Cell and Subcellular Manipulation and Detection

    DEFF Research Database (Denmark)

    Buch-Månson, Nina

    , a wealth of NS array materials, geometries and cellular applications have beenexplored, and this diversity has naturally led to some contradicting observations for the cell-NSinterface and basic cell behavior. Therefore, careful, systematic studies are still needed toimprove the fundamental understanding...... on different NSarray geometries and materials, both through theoretical modeling and experiments.We first seek to improve the fundamental understanding of the cell-NS interface bytheoretical considerations of the energy balance between the cost of membrane deformationaround the NSs and the favorable gain...... these two cell settling states dependshighly on the single-NS geometry. Thus, a generic cell settling prediction tool as a function ofNS diameter and length is established. We also show that the prediction depends on certain cellproperties, but that the sensitivity to changes in these is determined...

  5. Impacts of Coulomb Interactions on the Magnetic Responses of Excitonic Complexes in Single Semiconductor Nanostructures

    Directory of Open Access Journals (Sweden)

    Fu Ying-Jhe

    2010-01-01

    Full Text Available Abstract We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs and quantum rings (QRs. For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X, biexcitons (XX, and positive trions (X−. For negative trions (X− in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections.

  6. Large-scale synthesis of single-crystalline MgO with bone-like nanostructures

    International Nuclear Information System (INIS)

    Niu Haixia; Yang Qing; Tang Kaibin; Xie Yi

    2006-01-01

    Uniform bone-like MgO nanocrystals have been prepared via a solvothermal process using commercial Mg powders as the starting material in the absence of any catalyst or surfactant followed by a subsequent calcination. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) measurements indicate that the product consists of a large quantity of bone-like nanocrystals with lengths of 120-200 nm. The widths of these nanocrystals at both ends are in the range of 20-50 nm, which are 3-20 nm wider than those of the middle parts. Explorations of X-ray diffraction (XRD) and selected area electronic diffraction (SAED) exhibit that the product is high-quality cubic single-crystalline nanocrystals. The photoluminescence (PL) measurement suggests that the product has an intensive emission centered at 410 nm, showing that the product has potential application in optical devices. The advantages of our method lie in high yield, the easy availability of the starting materials and permitting large-scale production at low cost. The growth mechanism was proposed to be related with solvent's oxidation in the precursor formation process and following nucleation and mass-transfer in the decomposition of the precursor

  7. Single- and Multilayered Nanostructures via Laser-Induced Block Copolymer Self-Assembly

    Science.gov (United States)

    Majewski, Pawel; Yager, Kevin; Rahman, Atikur; Black, Charles

    We present a novel method of accelerated self-assembly of block copolymer thin films utilizing laser light, called Laser Zone Annealing (LZA). In our approach, steep temperature transients are induced in block copolymer films by rastering narrowly focused laser line over the light-absorbing substrate. Extremely steep temperature gradients accelerate the process of self-assembly by several orders-of-magnitude compared to conventional oven annealing, and, when coupled to photo-thermal shearing, lead to global alignment of block copolymer domains assessed by GISXAS diffraction studies and real-space SEM imaging. We demonstrate monolithic alignment of various block-copolymer thin films including PS-b-PMMA, PS-b-PEO, PS-b-P2VP, PS-b-PI and observe different responsiveness to the shearing rate depending on the characteristic relaxation timescale of the particular material. Subsequently, we use the aligned polymeric films as templates for synthesis of single- and multi-layered arrays of inorganic, metallic or semiconducting nanowires and nanomeshes and investigate their anisotropic electro-optical properties. Research carried out in part at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.

  8. Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

    Science.gov (United States)

    Mosby, James Matthew

    different sizes, shapes, and surface areas. This is advantageous because high surface area materials benefit from improved kinetics for solid state transformations and from decreases in mechanical degradation that occurs during the lithiation and delithiation of battery materials. Intermetallic materials are an alternative to conventional anode materials because they have high capacities and react reversibly with lithium at potentials that hinder the dendrite formation of metallic lithium. Unfortunately, the volume expansion associated with the lithiation and delithiation of intermetallic materials is usually large (over 300%). With this in mind a procedure for the electrodeposition of Cu2Sb from aqueous solutions was developed and is presented in this thesis. Cu2Sb is an intermetallic that lithiates at potentials more positive than the potential needed to plate lithium metal, and has a volume expansion less than 100%. Electrodeposition of an intermetallic with a relatively small volume expansion and with high surface area morphology should dramatically reduce material degradation during battery cycling, thus promoting the life of the material. To electrodeposit Cu2Sb from aqueous solutions, soluble salts of Cu2+ and Sb3+ were needed. There are many Cu2+ salts that are highly soluble in water, but most Sb 3+ salts cause formation of Sb2O3 in aqueous solutions. To obtain Sb3+ in aqueous solutions, citric acid was used as a complexing agent. The results presented in this dissertation show that solution speciation plays an important role in the electrochemistry of aqueous citrate solutions of both copper and antimony. The cyclic voltammograms (CVs) presented here show that the reduction potential of Cu2+ shifted in the negative direction and the reduction potential of Sb 3+ shifted in the positive direction with an increase in pH. Also, Cu2Sb films were deposited at a single potential (-1050 mV vs. SSCE) from aqueous solutions at pH 6. We determined that the deposition

  9. Application of a COTS Resource Optimization Framework to the SSN Sensor Tasking Domain - Part I: Problem Definition

    Science.gov (United States)

    Tran, T.

    With the onset of the SmallSat era, the RSO catalog is expected to see continuing growth in the near future. This presents a significant challenge to the current sensor tasking of the SSN. The Air Force is in need of a sensor tasking system that is robust, efficient, scalable, and able to respond in real-time to interruptive events that can change the tracking requirements of the RSOs. Furthermore, the system must be capable of using processed data from heterogeneous sensors to improve tasking efficiency. The SSN sensor tasking can be regarded as an economic problem of supply and demand: the amount of tracking data needed by each RSO represents the demand side while the SSN sensor tasking represents the supply side. As the number of RSOs to be tracked grows, demand exceeds supply. The decision-maker is faced with the problem of how to allocate resources in the most efficient manner. Braxton recently developed a framework called Multi-Objective Resource Optimization using Genetic Algorithm (MOROUGA) as one of its modern COTS software products. This optimization framework took advantage of the maturing technology of evolutionary computation in the last 15 years. This framework was applied successfully to address the resource allocation of an AFSCN-like problem. In any resource allocation problem, there are five key elements: (1) the resource pool, (2) the tasks using the resources, (3) a set of constraints on the tasks and the resources, (4) the objective functions to be optimized, and (5) the demand levied on the resources. In this paper we explain in detail how the design features of this optimization framework are directly applicable to address the SSN sensor tasking domain. We also discuss our validation effort as well as present the result of the AFSCN resource allocation domain using a prototype based on this optimization framework.

  10. Single-step direct fabrication of pillar-on-pore hybrid nanostructures in anodizing aluminum for superior superhydrophobic efficiency.

    Science.gov (United States)

    Jeong, Chanyoung; Choi, Chang-Hwan

    2012-02-01

    Conventional electrochemical anodizing processes of metals such as aluminum typically produce planar and homogeneous nanopore structures. If hydrophobically treated, such 2D planar and interconnected pore structures typically result in lower contact angle and larger contact angle hysteresis than 3D disconnected pillar structures and, hence, exhibit inferior superhydrophobic efficiency. In this study, we demonstrate for the first time that the anodizing parameters can be engineered to design novel pillar-on-pore (POP) hybrid nanostructures directly in a simple one-step fabrication process so that superior surface superhydrophobicity can also be realized effectively from the electrochemical anodization process. On the basis of the characteristic of forming a self-ordered porous morphology in a hexagonal array, the modulation of anodizing voltage and duration enabled the formulation of the hybrid-type nanostructures having controlled pillar morphology on top of a porous layer in both mild and hard anodization modes. The hybrid nanostructures of the anodized metal oxide layer initially enhanced the surface hydrophilicity significantly (i.e., superhydrophilic). However, after a hydrophobic monolayer coating, such hybrid nanostructures then showed superior superhydrophobic nonwetting properties not attainable by the plain nanoporous surfaces produced by conventional anodization conditions. The well-regulated anodization process suggests that electrochemical anodizing can expand its usefulness and efficacy to render various metallic substrates with great superhydrophilicity or -hydrophobicity by directly realizing pillar-like structures on top of a self-ordered nanoporous array through a simple one-step fabrication procedure.

  11. Metal-coated semiconductor nanostructures and simulation of photon extraction and coupling to optical fibers for a solid-state single-photon source

    International Nuclear Information System (INIS)

    Suemune, Ikuo; Nakajima, Hideaki; Liu, Xiangming; Odashima, Satoru; Asano, Tomoya; Iijima, Hitoshi; Huh, Jae-Hoon; Idutsu, Yasuhiro; Sasakura, Hirotaka; Kumano, Hidekazu

    2013-01-01

    We have realized metal-coated semiconductor nanostructures for a stable and efficient single-photon source (SPS) and demonstrated improved single-photon extraction efficiency by the selection of metals and nanostructures. We demonstrate with finite-difference time-domain (FDTD) simulations that inclination of a pillar sidewall, which changes the structure to a nanocone, is effective in improving the photon extraction efficiency. We demonstrate how such nanocone structures with inclined sidewalls are fabricated with reactive ion etching. With the optimized design, a photon extraction efficiency to outer airside as high as ∼97% generated from a quantum dot in a nanocone structure is simulated, which is the important step in realizing SPS on-demand operations. We have also examined the direct contact of such a metal-embedded nanocone structure with a single-mode fiber facet as a simple and practical method for preparing fiber-coupled SPS and demonstrated practical coupling efficiencies of ∼16% with FDTD simulation. (paper)

  12. Properties of nano-structured Ni/YSZ anodes fabricated from plasma sprayable NiO/YSZ powder prepared by single step solution combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, B. Shri; Balaji, N.; Kumar, S. Senthil; Aruna, S.T., E-mail: staruna194@gmail.com

    2016-12-15

    Highlights: • Preparation of plasma grade NiO/YSZ powder in single step. • Fabrication of nano-structured Ni/YSZ coating. • Conductivity of 600 S/cm at 800 °C. - Abstract: NiO/YSZ anode coatings are fabricated by atmospheric plasma spraying at different plasma powers from plasma grade NiO/YSZ powders that are prepared in a single step by solution combustion method. The process adopted is devoid of multi-steps that are generally involved in conventional spray drying or fusing and crushing methods. Density of the coating increased and porosity decreased with increase in the plasma power of deposition. An ideal nano-structured Ni/YSZ anode encompassing nano YSZ particles, nano Ni particles and nano pores is achieved on reducing the coating deposited at lower plasma powers. The coating exhibit porosities in the range of 27%, sufficient for anode functional layers. Electronic conductivity of the coatings is in the range of 600 S/cm at 800 °C.

  13. Generation of single attosecond pulse within one atomic unit by using multi-cycle inhomogeneous polarization gating technology in bowtie-shaped nanostructure

    Science.gov (United States)

    Feng, Liqiang; Liu, Hang

    2018-04-01

    The generations of high-order harmonic spectra and single attosecond pulses (SAPs) driven by the multi-cycle inhomogeneous polarization gating (PG) technology in the bowtie-shaped nanostructure have been theoretically investigated. It is found that by setting the bowtie-shaped nanostructure along the driven laser polarization direction, not only the extension of the harmonic cutoff can be achieved, caused by the surface plasmon polaritons, but also the modulations of the harmonics can be decreased, caused by the PG technology and the inhomogeneous effect. As a result, the contribution of the harmonic plateau is only from one harmonic emission peak with the dominant short quantum path. Further, by properly adding a half-cycle pulse into the driven laser field, the harmonic emission process can be precisely controlled in the half-cycle duration and a supercontinuum with the bandwidth of 263 eV can be obtained. Finally, by directly superposing the harmonics from this supercontinuum, a SAP with the full width at half maximum of 23 as can be obtained, which is shorter than one atomic unit.

  14. Advances on the nanostructuration of magnetic molecules on surfaces: the case of single-molecule magnets (SMM).

    Science.gov (United States)

    Gómez-Segura, Jordi; Veciana, Jaume; Ruiz-Molina, Daniel

    2007-09-28

    SMMs exhibit slow magnetization relaxation rates characteristic of nanodomain particles whose origin is however on individual molecules. For this reason, they have attracted much interest due to their potential applications in high-density information storage devices and quantum computing applications, where for instance, each molecule can be used as a magnetic bit of information. However, for this to become a reality, several basic studies such as their deposition on surfaces are still highly required. Here we will revise all the experimental approximations that have been so far reported for their addressing, nanostructuration and study on surfaces, from the use of stamps as templates to their anchorage to gold surface through the use of thiol-based ligands. It is also important to emphasize that the results and methodologies described along this review are applicable not only to SMMs but to any molecular material.

  15. Characterization of the immune response and evaluation of the protective capacity of rSsnA against Streptococcus suis infection in pigs

    DEFF Research Database (Denmark)

    Gómez-Gascón, Lidia; Cardoso-Toset, Fernando; Tarradas, Carmen

    2016-01-01

    were evaluated. Moreover the composition of peripheral blood leukocyte populations was studied in infected animals. The results show that the immunization of piglets with rSsnA elicits a significant humoral antibody response. However, the antibody response is not reflected in protection of pigs...

  16. KONTRIBUSI DISIPLIN KERJA, MOTIVASI KERJA, DAN PERSEPSI GURU TENTANG GAYA KEPEMIMPINAN KEPALA SEKOLAH TERHADAP UNJUK KERJA GURU SMP NEGERI SSN DI KABUPATEN SEMARANG

    Directory of Open Access Journals (Sweden)

    Nuk Isdiyati

    2015-07-01

    Full Text Available The purpose of this study is to determine whether there is Contribution of work discipline, work motivation, and teacher perceptions about headmaster leadership style towards teacher performance at SMP N with National Standard School (SSN Semarang. This study includes quantitative expo facto research. The population in this study were teachers at SMP N with National Standard School (SSN Semarang counted 302. The samples in this study are 161 teachers obtained from the table that was developed by Isaac and Michael. The determination of sampling in this study uses with a sample random sampling. The data are collected by survey or questionnaire. Data analysis technique uses multiple linear regression analysis of test preconditions data that is normality test, multicollinearity, heteroscedasticity, autocorrelation test and test. The results showed: (1 there is a contribution to the discipline of work, work motivation and teacher perceptions about headmaster leadership style towards teacher performance at SMP N with National Standard School (SSN Semarang, as shown by the acquisition of the F test with probability value 0.000 <0.05. From the results of data analysis, the R2 value counted 0.429 it means that there are contributions of work discipline, motivation, and teacher perceptions about headmaster leadership style towards teacher performance at SMP N with National Standard School (SSN Semarang counted 42.9%; 2 there is a contribution of work discipline towards teacher performance at SMP N with National Standard School (SSN Semarang, this is indicated with the acquisition probability value <0.05 with the effective contribution counted 12.82%; 3 there is a contribution of work motivation towards teacher performance at SMP N with National Standard School (SSN Semarang, it is shown by the acquisition probability value <0.05 with the effective contribution counted 12.86%; 4 there is contribution of teacher perceptions about headmaster leadership style

  17. Localization microscopy of DNA in situ using Vybrant{sup ®} DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution

    Energy Technology Data Exchange (ETDEWEB)

    Żurek-Biesiada, Dominika [Laboratory of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków (Poland); Szczurek, Aleksander T. [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Prakash, Kirti [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Institute for Pharmacy and Molecular Biotechnology (IPMB), University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg (Germany); Mohana, Giriram K. [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Lee, Hyun-Keun [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Department of Physics, University of Mainz (JGU), Staudingerweg 7, 55128 Mainz (Germany); Roignant, Jean-Yves [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Birk, Udo J. [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Department of Physics, University of Mainz (JGU), Staudingerweg 7, 55128 Mainz (Germany); Dobrucki, Jurek W., E-mail: jerzy.dobrucki@uj.edu.pl [Laboratory of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków (Poland); Cremer, Christoph, E-mail: c.cremer@imb-mainz.de [Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz (Germany); Institute for Pharmacy and Molecular Biotechnology (IPMB), University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg (Germany); Department of Physics, University of Mainz (JGU), Staudingerweg 7, 55128 Mainz (Germany)

    2016-05-01

    Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant{sup ®} DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei of fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10{sup 6} signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100 nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. - Highlights: • Super-resolution imaging of nuclear DNA with Vybrant Violet and blue excitation. • 90nm resolution images of DNA structures in optically thick eukaryotic nuclei. • Enhanced resolution confirms the existence of DNA-free regions inside the nucleus. • Optimized imaging conditions enable multicolor super-resolution imaging.

  18. Quantum optics with semiconductor nanostructures

    CERN Document Server

    Jahnke, Frank

    2012-01-01

    A guide to the theory, application and potential of semiconductor nanostructures in the exploration of quantum optics. It offers an overview of resonance fluorescence emission.$bAn understanding of the interaction between light and matter on a quantum level is of fundamental interest and has many applications in optical technologies. The quantum nature of the interaction has recently attracted great attention for applications of semiconductor nanostructures in quantum information processing. Quantum optics with semiconductor nanostructures is a key guide to the theory, experimental realisation, and future potential of semiconductor nanostructures in the exploration of quantum optics. Part one provides a comprehensive overview of single quantum dot systems, beginning with a look at resonance fluorescence emission. Quantum optics with single quantum dots in photonic crystal and micro cavities are explored in detail, before part two goes on to review nanolasers with quantum dot emitters. Light-matter interaction...

  19. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    NARCIS (Netherlands)

    Dekker, N.H.; Ha, S.; Janissen, R.; Ussembayev, Y.; van Oene, M.M.; Solano Hermosilla, B.P.

    2016-01-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and

  20. Single photon emission up to liquid nitrogen temperature from charged excitons confined in GaAs-based epitaxial nanostructures

    NARCIS (Netherlands)

    Dusanowski, L.; Syperek, M.; Marynski, A.; Li, L.H.; Misiewicz, J.; Höfling, S.; Kamp, M.; Fiore, A.; Sek, G.

    2015-01-01

    We demonstrate a non-classical photon emitter at near infrared wavelength based on a single (In,Ga)As/GaAs epitaxially grown columnar quantum dot. Charged exciton complexes have been identified in magneto-photoluminescence. Photon auto-correlation histograms from the recombination of a trion

  1. Analytic device including nanostructures

    KAUST Repository

    Di Fabrizio, Enzo M.; Fratalocchi, Andrea; Totero Gongora, Juan Sebastian; Coluccio, Maria Laura; Candeloro, Patrizio; Cuda, Gianni

    2015-01-01

    A device for detecting an analyte in a sample comprising: an array including a plurality of pixels, each pixel including a nanochain comprising: a first nanostructure, a second nanostructure, and a third nanostructure, wherein size of the first nanostructure is larger than that of the second nanostructure, and size of the second nanostructure is larger than that of the third nanostructure, and wherein the first nanostructure, the second nanostructure, and the third nanostructure are positioned on a substrate such that when the nanochain is excited by an energy, an optical field between the second nanostructure and the third nanostructure is stronger than an optical field between the first nanostructure and the second nanostructure, wherein the array is configured to receive a sample; and a detector arranged to collect spectral data from a plurality of pixels of the array.

  2. A third kind growth model of tetrapod: Rod-based single crystal ZnO tetrapod nanostructure

    International Nuclear Information System (INIS)

    Gong, J.F.; Huang, H.B.; Wang, Z.Q.; Zhao, X.N.; Yang, S.G.; Yu Zhongzhen

    2008-01-01

    In this paper, rod-based ZnO tetrapods were successfully synthesized by burning Zn particles in air covered with two firebricks. The products show hexagonal wurtzite phase. The microstructures of the tetrapod were studied carefully by scanning electron microscope (SEM), transmission electron microscope (TEM), SAED and HRTEM. The results show that tetrapod has single crystalline phase with one broader nanorod growing along [0 0 0 1] direction, three triangular nanosheets, growing out of the three trisection planes along [101-bar0] direction, and three epitaxial nanowires, growing from each tip of the triangular nanosheets. Based on the experimental results, a rod-based growth model was proposed to interpret its growth mechanism. Room temperature photoluminescence spectrum reveals that the ZnO tetrapods have ultra violet (UV) emission band (389 nm) and a green emission band (517 nm)

  3. Nanostructures based on quantum dots for application in promising methods of single- and multiphoton imaging and diagnostics

    Science.gov (United States)

    Nabiev, I. R.

    2017-01-01

    Molecules recognizing biomarkers of diseases (monoclonal antibodies (monoABs)) are often too large for biomedical applications, and the conditions that are used to bind them with nanolabels lead to disordered orientation of monoABs with respect to the nanoparticle surface. Extremely small nanoprobes, designed via oriented conjugation of quantum dots (QDs) with single-domain antibodies (sdABs) derived from the immunoglobulin of llama and produced in the E. coli culture, have a hydrodynamic diameter less than 12 nm and contain equally oriented sdAB molecules on the surface of each QD. These nanoprobes exhibit excellent specificity and sensitivity in quantitative determination of a small number of cells expressing biomarkers. In addition, the higher diffusion coefficient of sdABs makes it possible to perform immunohistochemical analysis in bulk tissue, inaccessible for conventional monoABs. The necessary conditions for implementing high-quality immunofluorescence diagnostics are a high specificity of labeling and clear differences between the fluorescence of nanoprobes and the autofluorescence of tissues. Multiphoton micros-copy with excitation in the near-IR spectral range, which is remote from the range of tissue autofluorescence excitation, makes it possible to solve this problem and image deep layers in biological tissues. The two-photon absorption cross sections of CdSe/ZnS QDs conjugated with sdABs exceed the corresponding values for organic fluorophores by several orders of magnitude. These nanoprobes provide clear discrimination between the regions of tumor and normal tissues with a ratio of the sdAB fluorescence to the tissue autofluorescence upon two-photon excitation exceeding that in the case of single-photon excitation by a factor of more than 40. The data obtained indicate that the sdAB-QD conjugates used as labels provide the same, or even better, quality as the "gold standard" of immunohistochemical diagnostics. The developed nanoprobes are expected to

  4. Mechanical design of DNA nanostructures

    Science.gov (United States)

    Castro, Carlos E.; Su, Hai-Jun; Marras, Alexander E.; Zhou, Lifeng; Johnson, Joshua

    2015-03-01

    Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems.Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07153k

  5. Single-step in-situ synthesis and optical properties of ZnSe nanostructured dielectric nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Chirantan; Rahaman Molla, Atiar; Tarafder, Anal; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in [CSIR-Central Glass and Ceramic Research Institute, Glass Science and Technology Section, Glass Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Kr Mishra, Manish; De, Goutam [CSIR-Central Glass and Ceramic Research Institute, Nano-Structured Materials Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Goswami, Madhumita; Kothiyal, G. P. [Glass and Advanced Ceramics Division, Bhaba Atomic Research Centre, Trombay, 400085 Mumbai (India)

    2014-04-07

    This work provides the evidence of visible red photoluminescent light emission from ZnSe nanocrystals (NCs) grown within a dielectric (borosilicate glass) matrix synthesized by a single step in-situ technique for the first time and the NC sizes were controlled by varying only the concentration of ZnSe in glass matrix. The ZnSe NCs were investigated by UV-Vis optical absorption spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM). The sizes of the ZnSe NCs estimated from the TEM images are found to alter in the range of 2–53 nm. Their smaller sizes of the NCs were also calculated by using the optical absorption spectra and the effective mass approximation model. The band gap enlargements both for carrier and exciton confinements were evaluated and found to be changed in the range of 0–1.0 eV. The Raman spectroscopic studies showed blue shifted Raman peaks of ZnSe at 295 and 315 cm{sup −1} indicating phonon confinement effect as well as compressive stress effect on the surface atoms of the NCs. Red photoluminescence in ZnSe-glass nanocomposite reveals a broad multiple-peak structure due to overlapping of emission from NC size related electron-hole recombination (∼707 nm) and emissions from defects to traps, which were formed due to Se and Zn vacancies signifying potential application in photonics.

  6. Synthesis of ferroelectric nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Roervik, Per Martin

    2008-12-15

    The increasing miniaturization of electric and mechanical components makes the synthesis and assembly of nanoscale structures an important step in modern technology. Functional materials, such as the ferroelectric perovskites, are vital to the integration and utility value of nanotechnology in the future. In the present work, chemical methods to synthesize one-dimensional (1D) nanostructures of ferroelectric perovskites have been studied. To successfully and controllably make 1D nanostructures by chemical methods it is very important to understand the growth mechanism of these nanostructures, in order to design the structures for use in various applications. For the integration of 1D nanostructures into devices it is also very important to be able to make arrays and large-area designed structures from the building blocks that single nanostructures constitute. As functional materials, it is of course also vital to study the properties of the nanostructures. The characterization of properties of single nanostructures is challenging, but essential to the use of such structures. The aim of this work has been to synthesize high quality single-crystalline 1D nanostructures of ferroelectric perovskites with emphasis on PbTiO3 , to make arrays or hierarchical nanostructures of 1D nanostructures on substrates, to understand the growth mechanisms of the 1D nanostructures, and to investigate the ferroelectric and piezoelectric properties of the 1D nanostructures. In Paper I, a molten salt synthesis route, previously reported to yield BaTiO3 , PbTiO3 and Na2Ti6O13 nanorods, was re-examined in order to elucidate the role of volatile chlorides. A precursor mixture containing barium (or lead) and titanium was annealed in the presence of NaCl at 760 degrees Celsius or 820 degrees Celsius. The main products were respectively isometric nanocrystalline BaTiO3 and PbTiO3. Nanorods were also detected, but electron diffraction revealed that the composition of the nanorods was

  7. Complex Nanostructures by Pulsed Droplet Epitaxy

    Directory of Open Access Journals (Sweden)

    Noboyuki Koguchi

    2011-06-01

    Full Text Available What makes three dimensional semiconductor quantum nanostructures so attractive is the possibility to tune their electronic properties by careful design of their size and composition. These parameters set the confinement potential of electrons and holes, thus determining the electronic and optical properties of the nanostructure. An often overlooked parameter, which has an even more relevant effect on the electronic properties of the nanostructure, is shape. Gaining a strong control over the electronic properties via shape tuning is the key to access subtle electronic design possibilities. The Pulsed Dropled Epitaxy is an innovative growth method for the fabrication of quantum nanostructures with highly designable shapes and complex morphologies. With Pulsed Dropled Epitaxy it is possible to combine different nanostructures, namely quantum dots, quantum rings and quantum disks, with tunable sizes and densities, into a single multi-function nanostructure, thus allowing an unprecedented control over electronic properties.

  8. Vortices and nanostructured superconductors

    CERN Document Server

    2017-01-01

    This book provides expert coverage of modern and novel aspects of the study of vortex matter, dynamics, and pinning in nanostructured and multi-component superconductors. Vortex matter in superconducting materials is a field of enormous beauty and intellectual challenge, which began with the theoretical prediction of vortices by A. Abrikosov (Nobel Laureate). Vortices, vortex dynamics, and pinning are key features in many of today’s human endeavors: from the huge superconducting accelerating magnets and detectors at the Large Hadron Collider at CERN, which opened new windows of knowledge on the universe, to the tiny superconducting transceivers using Rapid Single Flux Quanta, which have opened a revolutionary means of communication. In recent years, two new features have added to the intrinsic beauty and complexity of the subject: nanostructured/nanoengineered superconductors, and the discovery of a range of new materials showing multi-component (multi-gap) superconductivity. In this book, leading researche...

  9. Manganese Nanostructures and Magnetism

    Science.gov (United States)

    Simov, Kirie Rangelov

    The primary goal of this study is to incorporate adatoms with large magnetic moment, such as Mn, into two technologically significant group IV semiconductor (SC) matrices, e.g. Si and Ge. For the first time in the world, we experimentally demonstrate Mn doping by embedding nanostructured thin layers, i.e. delta-doping. The growth is observed by in-situ scanning tunneling microscopy (STM), which combines topographic and electronic information in a single image. We investigate the initial stages of Mn monolayer growth on a Si(100)(2x1) surface reconstruction, develop methods for classification of nanostructure types for a range of surface defect concentrations (1.0 to 18.2%), and subsequently encapsulate the thin Mn layer in a SC matrix. These experiments are instrumental in generating a surface processing diagram for self-assembly of monoatomic Mn-wires. The role of surface vacancies has also been studied by kinetic Monte Carlo modeling and the experimental observations are compared with the simulation results, leading to the conclusion that Si(100)(2x1) vacancies serve as nucleation centers in the Mn-Si system. Oxide formation, which happens readily in air, is detrimental to ferromagnetism and lessens the magnetic properties of the nanostructures. Therefore, the protective SC cap, composed of either Si or Ge, serves a dual purpose: it is both the embedding matrix for the Mn nanostructured thin film and a protective agent for oxidation. STM observations of partially deposited caps ensure that the nanostructures remain intact during growth. Lastly, the relationship between magnetism and nanostructure types is established by an in-depth study using x-ray magnetic circular dichroism (XMCD). This sensitive method detects signals even at coverages less than one atomic layer of Mn. XMCD is capable of discerning which chemical compounds contribute to the magnetic moment of the system, and provides a ratio between the orbital and spin contributions. Depending on the amount

  10. Many-particle theory of optical properties in low-dimensional nanostructures. Dynamics in single-walled carbon nanotubes and semiconductor quantum dots

    International Nuclear Information System (INIS)

    Malic, Ermin

    2008-01-01

    This work focuses on the theoretical investigation of optical properties of low-dimensional nanostructures, specifically single-walled carbon nanotubes (CNTs) and self-assembled InAs/GaAs quantum dots (QDs). The density-matrix formalism is applied to explain recent experimental results and to give insight into the underlying physics. A microscopic calculation of the absorption coefficient and the Rayleigh scattering cross section is performed by a novel approach combining the density-matrix formalism with the tight-binding wave functions. The calculated spectra of metallic nanotubes show a double-peaked structure resulting from the trigonal warping effect. The intensity ratios of the four lowest-lying transitions in both absorption and Rayleigh spectra can be explained by the different behavior of the optical matrix elements along the high-symmetry lines K-Γ and K-M. The Rayleigh line shape is predicted to be asymmetric, with an enhanced cross section for lower photon energies arising from non-resonant contributions of the optical susceptibility. Furthermore, the Coulomb interaction is shown to be maximal when the momentum transfer is low. For intersubband processes with a perpendicular momentum transfer, the coupling strength is reduced to less than 5%. The chirality and diameter dependence of the excitonic binding energy and the transition frequency are presented in Kataura plots. Furthermore, the influence of the surrounding environment on the optical properties of CNTs is investigated. Extending the confinement to all three spatial dimensions, semiconductor Bloch equation are derived to describe the dynamics in QD semiconductor lasers and amplifiers. A detailed microscopic analysis of the nonlinear turn-on dynamics of electrically pumped InAs/GaAs QD lasers is performed, showing the generation of relaxation oscillations on a nanosecond time scale in both the photon and charge carrier density. The theory predicts a strong damping of relaxation oscillations

  11. Many-particle theory of optical properties in low-dimensional nanostructures. Dynamics in single-walled carbon nanotubes and semiconductor quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Malic, Ermin

    2008-09-02

    This work focuses on the theoretical investigation of optical properties of low-dimensional nanostructures, specifically single-walled carbon nanotubes (CNTs) and self-assembled InAs/GaAs quantum dots (QDs). The density-matrix formalism is applied to explain recent experimental results and to give insight into the underlying physics. A microscopic calculation of the absorption coefficient and the Rayleigh scattering cross section is performed by a novel approach combining the density-matrix formalism with the tight-binding wave functions. The calculated spectra of metallic nanotubes show a double-peaked structure resulting from the trigonal warping effect. The intensity ratios of the four lowest-lying transitions in both absorption and Rayleigh spectra can be explained by the different behavior of the optical matrix elements along the high-symmetry lines K-{gamma} and K-M. The Rayleigh line shape is predicted to be asymmetric, with an enhanced cross section for lower photon energies arising from non-resonant contributions of the optical susceptibility. Furthermore, the Coulomb interaction is shown to be maximal when the momentum transfer is low. For intersubband processes with a perpendicular momentum transfer, the coupling strength is reduced to less than 5%. The chirality and diameter dependence of the excitonic binding energy and the transition frequency are presented in Kataura plots. Furthermore, the influence of the surrounding environment on the optical properties of CNTs is investigated. Extending the confinement to all three spatial dimensions, semiconductor Bloch equation are derived to describe the dynamics in QD semiconductor lasers and amplifiers. A detailed microscopic analysis of the nonlinear turn-on dynamics of electrically pumped InAs/GaAs QD lasers is performed, showing the generation of relaxation oscillations on a nanosecond time scale in both the photon and charge carrier density. The theory predicts a strong damping of relaxation oscillations

  12. Behaviour of a PWR with core protection system (SSN) in case of accidents due to power failure, ATWS and steam generator rupture

    International Nuclear Information System (INIS)

    Boncompagni, S.; Fulceri, P.; Oriolo, F.

    1985-01-01

    The results of the analysis of the transient fallowing internal and external power failure, without scram, in the nuclear power plant of the Italian Unified Nuclear Project are examined. The availability of ECCS is excluded while the breakage of a tube in each steam generator is supposed, togheter with the presence of an original safety system known as SSN (core protection system). Computations have been performed by using Mark 6 RELAP4 code. The study of the transient and the physical model used are briefly illustrated. Finally the results achieved are analysed

  13. Nanostructuring of Solar Cell Surfaces

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

    Solar energy is by far the most abundant renewable energy source available, but the levelized cost of solar energy is still not competitive with that of fossil fuels. Therefore there is a need to improve the power conversion effciency of solar cells without adding to the production cost. The main...... objective of this PhD thesis is to develop nanostructured silicon (Si) solar cells with higher power conversion efficiency using only scalable and cost-efficient production methods. The nanostructures, known as 'black silicon', are fabricated by single-step, maskless reactive ion etching and used as front...... texturing of different Si solar cells. Theoretically the nanostructure topology may be described as a graded refractive index in a mean-field approximation between air and Si. The optical properties of the developed black Si were simulated and experimentally measured. Total AM1.5G-weighted average...

  14. Nanostructures for protein drug delivery.

    Science.gov (United States)

    Pachioni-Vasconcelos, Juliana de Almeida; Lopes, André Moreni; Apolinário, Alexsandra Conceição; Valenzuela-Oses, Johanna Karina; Costa, Juliana Souza Ribeiro; Nascimento, Laura de Oliveira; Pessoa, Adalberto; Barbosa, Leandro Ramos Souza; Rangel-Yagui, Carlota de Oliveira

    2016-02-01

    Use of nanoscale devices as carriers for drugs and imaging agents has been extensively investigated and successful examples can already be found in therapy. In parallel, recombinant DNA technology together with molecular biology has opened up numerous possibilities for the large-scale production of many proteins of pharmaceutical interest, reflecting in the exponentially growing number of drugs of biotechnological origin. When we consider protein drugs, however, there are specific criteria to take into account to select adequate nanostructured systems as drug carriers. In this review, we highlight the main features, advantages, drawbacks and recent developments of nanostructures for protein encapsulation, such as nanoemulsions, liposomes, polymersomes, single-protein nanocapsules and hydrogel nanoparticles. We also discuss the importance of nanoparticle stabilization, as well as future opportunities and challenges in nanostructures for protein drug delivery.

  15. PREFACE: Nanostructured surfaces

    Science.gov (United States)

    Palmer, Richard E.

    2003-10-01

    We can define nanostructured surfaces as well-defined surfaces which contain lateral features of size 1-100 nm. This length range lies well below the micron regime but equally above the Ångstrom regime, which corresponds to the interatomic distances on single-crystal surfaces. This special issue of Journal of Physics: Condensed Matter presents a collection of twelve papers which together address the fabrication, characterization, properties and applications of such nanostructured surfaces. Taken together they represent, in effect, a status report on the rapid progress taking place in this burgeoning area. The first four papers in this special issue have been contributed by members of the European Research Training Network ‘NanoCluster’, which is concerned with the deposition, growth and characterization of nanometre-scale clusters on solid surfaces—prototypical examples of nanoscale surface features. The paper by Vandamme is concerned with the fundamentals of the cluster-surface interaction; the papers by Gonzalo and Moisala address, respectively, the optical and catalytic properties of deposited clusters; and the paper by van Tendeloo reports the application of transmission electron microscopy (TEM) to elucidate the surface structure of spherical particles in a catalyst support. The fifth paper, by Mendes, is also the fruit of a European Research Training Network (‘Micro-Nano’) and is jointly contributed by three research groups; it reviews the creation of nanostructured surface architectures from chemically-synthesized nanoparticles. The next five papers in this special issue are all concerned with the characterization of nanostructured surfaces with scanning tunnelling microscopy (STM) and atomic force microscopy (AFM). The papers by Bolotov, Hamilton and Dunstan demonstrate that the STM can be employed for local electrical measurements as well as imaging, as illustrated by the examples of deposited clusters, model semiconductor structures and real

  16. Irradiation-Induced Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Birtcher, R.C.; Ewing, R.C.; Matzke, Hj.; Meldrum, A.; Newcomer, P.P.; Wang, L.M.; Wang, S.X.; Weber, W.J.

    1999-08-09

    This paper summarizes the results of the studies of the irradiation-induced formation of nanostructures, where the injected interstitials from the source of irradiation are not major components of the nanophase. This phenomena has been observed by in situ transmission electron microscopy (TEM) in a number of intermetallic compounds and ceramics during high-energy electron or ion irradiations when the ions completely penetrate through the specimen. Beginning with single crystals, electron or ion irradiation in a certain temperature range may result in nanostructures composed of amorphous domains and nanocrystals with either the original composition and crystal structure or new nanophases formed by decomposition of the target material. The phenomenon has also been observed in natural materials which have suffered irradiation from the decay of constituent radioactive elements and in nuclear reactor fuels which have been irradiated by fission neutrons and other fission products. The mechanisms involved in the process of this nanophase formation are discussed in terms of the evolution of displacement cascades, radiation-induced defect accumulation, radiation-induced segregation and phase decomposition, as well as the competition between irradiation-induced amorphization and recrystallization.

  17. Assembly of barcode-like nucleic acid nanostructures.

    Science.gov (United States)

    Wang, Pengfei; Tian, Cheng; Li, Xiang; Mao, Chengde

    2014-10-15

    Barcode-like (BC) nanopatterns from programmed self-assembly of nucleic acids (DNA and RNA) are reported. BC nanostructures are generated by the introduction of open spaces at selected sites to an otherwise closely packed, plain, rectangle nucleic acid nanostructure. This strategy is applied to nanostructures assembled from both origami approach and single stranded tile approach. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Plasmonic Nanostructures for Biosensor Applications

    Science.gov (United States)

    Gadde, Akshitha

    Improving the sensitivity of existing biosensors is an active research topic that cuts across several disciplines, including engineering and biology. Optical biosensors are the one of the most diverse class of biosensors which can be broadly categorized into two types based on the detection scheme: label-based and label-free detection. In label-based detection, the target bio-molecules are labeled with dyes or tags that fluoresce upon excitation, indicating the presence of target molecules. Label-based detection is highly-sensitive, capable of single molecule detection depending on the detector type used. One method of improving the sensitivity of label-based fluorescence detection is by enhancement of the emission of the labels by coupling them with metal nanostructures. This approach is referred as plasmon-enhanced fluorescence (PEF). PEF is achieved by increasing the electric field around the nano metal structures through plasmonics. This increased electric field improves the enhancement from the fluorophores which in turn improves the photon emission from the fluorophores which, in turn, improves the limit of detection. Biosensors taking advantage of the plasmonic properties of metal films and nanostructures have emerged an alternative, low-cost, high sensitivity method for detecting labeled DNA. Localized surface plasmon resonance (LSPR) sensors employing noble metal nanostructures have recently attracted considerable attention as a new class of plasmonic nanosensors. In this work, the design, fabrication and characterization of plasmonic nanostructures is carried out. Finite difference time domain (FDTD) simulations were performed using software from Lumerical Inc. to design a novel LSPR structure that exhibit resonance overlapping with the absorption and emission wavelengths of quantum dots (QD). Simulations of a composite Au/SiO2 nanopillars on silicon substrate were performed using FDTD software to show peak plasmonic enhancement at QD emission wavelength

  19. Fabrication of shape controlled Fe3O4 nanostructure

    International Nuclear Information System (INIS)

    Zheng, Y.Y.; Wang, X.B.; Shang, L.; Li, C.R.; Cui, C.; Dong, W.J.; Tang, W.H.; Chen, B.Y.

    2010-01-01

    Shape-controlled Fe 3 O 4 nanostructure has been successfully prepared using polyethylene glycol as template in a water system at room temperature. Different morphologies of Fe 3 O 4 nanostructures, including spherical, cubic, rod-like, and dendritic nanostructure, were obtained by carefully controlling the concentration of the Fe 3+ , Fe 2+ , and the molecular weight of the polyethylene glycol. Transmission Electron Microscope images, X-ray powder diffraction patterns and magnetic properties were used to characterize the final product. This easy procedure for Fe 3 O 4 nanostructure fabrication offers the possibility of a generalized approach to the production of single and complex nanocrystalline oxide with tunable morphology.

  20. Advanced Magnetic Nanostructures

    CERN Document Server

    Sellmyer, David

    2006-01-01

    Advanced Magnetic Nanostructures is devoted to the fabrication, characterization, experimental investigation, theoretical understanding, and utilization of advanced magnetic nanostructures. Focus is on various types of 'bottom-up' and 'top-down' artificial nanostructures, as contrasted to naturally occurring magnetic nanostructures, such as iron-oxide inclusions in magnetic rocks, and to structures such as perfect thin films. Chapter 1 is an introduction into some basic concepts, such as the definitions of basic magnetic quantities. Chapters 2-4 are devoted to the theory of magnetic nanostructures, Chapter 5 deals with the characterization of the structures, and Chapters 6-10 are devoted to specific systems. Applications of advanced magnetic nanostructures are discussed in Chapters11-15 and, finally, the appendix lists and briefly discusses magnetic properties of typical starting materials. Industrial and academic researchers in magnetism and related areas such as nanotechnology, materials science, and theore...

  1. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  2. Nanostructured Materials for Magnetoelectronics

    CERN Document Server

    Mikailzade, Faik

    2013-01-01

    This book provides an up-to-date review of nanometer-scale magnetism and focuses on the investigation of the basic properties of magnetic nanostructures. It describes a wide range of physical aspects together with theoretical and experimental methods. A broad overview of the latest developments in this emerging and fascinating field of nanostructured materials is given with emphasis on the practical understanding and operation of submicron devices based on nanostructured magnetic materials.

  3. Injection moulding antireflective nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe Sandvik; Mortensen, N. Asger

    2014-01-01

    We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used in an inject......We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used...

  4. Injection moulding antireflective nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe Sandvik; Mortensen, N. Asger

    We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used in an inject......We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used...

  5. Nanostructured layers of thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Jeffrey J.; Lynch, Jared; Coates, Nelson; Forster, Jason; Sahu, Ayaskanta; Chabinyc, Michael; Russ, Boris

    2018-01-30

    This disclosure provides systems, methods, and apparatus related to thermoelectric materials. In one aspect, a method includes providing a plurality of nanostructures. The plurality of nanostructures comprise a thermoelectric material, with each nanostructure of the plurality of nanostructures having first ligands disposed on a surface of the nanostructure. The plurality of nanostructures is mixed with a solution containing second ligands and a ligand exchange process occurs in which the first ligands disposed on the plurality of nanostructures are replaced with the second ligands. The plurality of nanostructures is deposited on a substrate to form a layer. The layer is thermally annealed.

  6. Method to deterministically study photonic nanostructures in different experimental instruments

    NARCIS (Netherlands)

    Husken, B.H.; Woldering, L.A.; Blum, Christian; Tjerkstra, R.W.; Vos, Willem L.

    2009-01-01

    We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the

  7. Hydrogen adsorption in carbon nanostructures compared

    NARCIS (Netherlands)

    Schimmel, H.G.; Nijkamp, M.G.; Kearley, G.J.; Rivera, A.; de Jong, K.P.; Mulder, F.M.

    2004-01-01

    Recent reports continue to suggest high hydrogen storage capacities for some carbon nanostructures due to a stronger interaction between hydrogen and carbon. Here the interaction of hydrogen with activated charcoal, carbon nanofibers, single walled carbon nanotubes (SWNT), and electron beam ‘opened’

  8. A hierarchical nanostructure consisting of amorphous MnO{sub 2}, Mn{sub 3}O{sub 4} nanocrystallites, and single-crystalline MnOOH nanowires for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chi-Chang; Hung, Ching-Yun [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30013 (China); Chang, Kuo-Hsin [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30013 (China); Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China); Yang, Yi-Lin [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China)

    2011-01-15

    In this communication, a porous hierarchical nanostructure consisting of amorphous MnO{sub 2} (a-MnO{sub 2}), Mn{sub 3}O{sub 4} nanocrystals, and single-crystalline MnOOH nanowires is designed for the supercapacitor application, which is prepared by a simple two-step electrochemical deposition process. Because of the gradual co-transformation of Mn{sub 3}O{sub 4} nanocrystals and a-MnO{sub 2} nanorods into an amorphous manganese oxide, the cycle stability of a-MnO{sub 2} is obviously enhanced by adding Mn{sub 3}O{sub 4}. This unique ternary oxide nanocomposite with 100-cycle CV activation exhibits excellent capacitive performances, i.e., excellent reversibility, high specific capacitances (470 F g{sup -1} in CaCl{sub 2}), high power property, and outstanding cycle stability. The highly porous microstructures of this composite before and after the 10,000-cycle CV test are examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). (author)

  9. Nuclear spins in nanostructures

    International Nuclear Information System (INIS)

    Coish, W.A.; Baugh, J.

    2009-01-01

    We review recent theoretical and experimental advances toward understanding the effects of nuclear spins in confined nanostructures. These systems, which include quantum dots, defect centers, and molecular magnets, are particularly interesting for their importance in quantum information processing devices, which aim to coherently manipulate single electron spins with high precision. On one hand, interactions between confined electron spins and a nuclear-spin environment provide a decoherence source for the electron, and on the other, a strong effective magnetic field that can be used to execute local coherent rotations. A great deal of effort has been directed toward understanding the details of the relevant decoherence processes and to find new methods to manipulate the coupled electron-nuclear system. A sequence of spectacular new results have provided understanding of spin-bath decoherence, nuclear spin diffusion, and preparation of the nuclear state through dynamic polarization and more general manipulation of the nuclear-spin density matrix through ''state narrowing.'' These results demonstrate the richness of this physical system and promise many new mysteries for the future. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  10. Phonon engineering for nanostructures.

    Energy Technology Data Exchange (ETDEWEB)

    Aubry, Sylvie (Stanford University); Friedmann, Thomas Aquinas; Sullivan, John Patrick; Peebles, Diane Elaine; Hurley, David H. (Idaho National Laboratory); Shinde, Subhash L.; Piekos, Edward Stanley; Emerson, John Allen

    2010-01-01

    Understanding the physics of phonon transport at small length scales is increasingly important for basic research in nanoelectronics, optoelectronics, nanomechanics, and thermoelectrics. We conducted several studies to develop an understanding of phonon behavior in very small structures. This report describes the modeling, experimental, and fabrication activities used to explore phonon transport across and along material interfaces and through nanopatterned structures. Toward the understanding of phonon transport across interfaces, we computed the Kapitza conductance for {Sigma}29(001) and {Sigma}3(111) interfaces in silicon, fabricated the interfaces in single-crystal silicon substrates, and used picosecond laser pulses to image the thermal waves crossing the interfaces. Toward the understanding of phonon transport along interfaces, we designed and fabricated a unique differential test structure that can measure the proportion of specular to diffuse thermal phonon scattering from silicon surfaces. Phonon-scale simulation of the test ligaments, as well as continuum scale modeling of the complete experiment, confirmed its sensitivity to surface scattering. To further our understanding of phonon transport through nanostructures, we fabricated microscale-patterned structures in diamond thin films.

  11. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  12. Enhanced structural stability of DNA origami nanostructures by graphene encapsulation

    International Nuclear Information System (INIS)

    Matković, Aleksandar; Vasić, Borislav; Pešić, Jelena; Gajić, Radoš; Prinz, Julia; Bald, Ilko; Milosavljević, Aleksandar R

    2016-01-01

    We demonstrate that a single-layer graphene replicates the shape of DNA origami nanostructures very well. It can be employed as a protective layer for the enhancement of structural stability of DNA origami nanostructures. Using the AFM based manipulation, we show that the normal force required to damage graphene encapsulated DNA origami nanostructures is over an order of magnitude greater than for the unprotected ones. In addition, we show that graphene encapsulation offers protection to the DNA origami nanostructures against prolonged exposure to deionized water, and multiple immersions. Through these results we demonstrate that graphene encapsulated DNA origami nanostructures are strong enough to sustain various solution phase processing, lithography and transfer steps, thus extending the limits of DNA-mediated bottom-up fabrication. (paper)

  13. Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    El-Said, A. S., E-mail: elsaid@kfupm.edu.sa, E-mail: a.s.el-said@hzdr.de [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden (Germany); Physics Department, Faculty of Science, Mansoura University, 35516 Mansoura (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Centre for Theoretical Physics, British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); Djebli, M. [Theoretical Physics Laboratory, Faculty of Physics USTHB, B.P. 32 Bab Ezzour, 16079 Algiers (Algeria)

    2014-06-09

    Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

  14. Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

    International Nuclear Information System (INIS)

    El-Said, A. S.; Moslem, W. M.; Djebli, M.

    2014-01-01

    Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

  15. Self-assembled nanostructures

    CERN Document Server

    Zhang, Jin Z; Liu, Jun; Chen, Shaowei; Liu, Gang-yu

    2003-01-01

    Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.

  16. A significant reduction of ice adhesion on nanostructured surfaces that consist of an array of single-walled carbon nanotubes: A molecular dynamics simulation study

    Science.gov (United States)

    Bao, Luyao; Huang, Zhaoyuan; Priezjev, Nikolai V.; Chen, Shaoqiang; Luo, Kai; Hu, Haibao

    2018-04-01

    It is well recognized that excessive ice accumulation at low-temperature conditions can cause significant damage to civil infrastructure. The passive anti-icing surfaces provide a promising solution to suppress ice nucleation and enhance ice removal. However, despite extensive efforts, it remains a challenge to design anti-icing surfaces with low ice adhesion. Using all-atom molecular dynamics (MD) simulations, we show that surfaces with single-walled carbon nanotube array (CNTA) significantly reduce ice adhesion due to the extremely low solid areal fraction. It was found that the CNTA surface exhibits up to a 45% decrease in the ice adhesion strength in comparison with the atomically smooth graphene surface. The details of the ice detachment from the CNTA surface were examined for different water-carbon interaction energies and temperatures of the ice cube. Remarkably, the results of MD simulations demonstrate that the ice detaching strength depends linearly on the ratio of the ice-surface interaction energy and the ice temperature. These results open the possibility for designing novel robust surfaces with low ice adhesion for passive anti-icing applications.

  17. Ultrasensitive electrochemical detection of microRNA-21 combining layered nanostructure of oxidized single-walled carbon nanotubes and nanodiamonds by hybridization chain reaction.

    Science.gov (United States)

    Liu, Lingzhi; Song, Chao; Zhang, Zhang; Yang, Juan; Zhou, Lili; Zhang, Xing; Xie, Guoming

    2015-08-15

    Measurement of microRNA (miRNA) levels in body fluids is a crucial tool for the early diagnosis and prognosis of cancers. In this study, we developed an electrochemical assay to detect miRNA-21 by fabricating the electrode with layer-by-layer assembly of oxidized single-walled carbon nanotubes and nanodiamonds. Tetrahedron-structured probes with free-standing probe on the top served as receptors to hybridize with target miRNA directly. The probes were immobilized on the deposited gold nanoparticles through a well-established strong Au-S bond. The electrochemical signal was mainly derived from an ultrasensitive pattern by combining hybridization chain reaction with DNA-functionalized AuNPs, which provided DNAzyme to catalyze H2O2 reduction. Differential pulse voltammetry was applied to record the electrochemical signals, which was increased linearly with the target miRNA-21, and the linear detection range was 10 fM to 1.0 nM. The limit of detection reached 1.95 fM (S/N=3), and the proposed biosensor exhibited good reproducibility and stability, as well as high sensitivity. Hence, this biosensor has a promising potential in clinical application. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Freestanding nanostructures via reactive ion beam angled etching

    Directory of Open Access Journals (Sweden)

    Haig A. Atikian

    2017-05-01

    Full Text Available Freestanding nanostructures play an important role in optical and mechanical devices for classical and quantum applications. Here, we use reactive ion beam angled etching to fabricate optical resonators in bulk polycrystalline and single crystal diamond. Reported quality factors are approximately 30 000 and 286 000, respectively. The devices show uniformity across 25 mm samples, a significant improvement over comparable techniques yielding freestanding nanostructures.

  19. Nanostructured materials for hydrogen storage

    Science.gov (United States)

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  20. Nanostructures from nanoparticles

    International Nuclear Information System (INIS)

    Mendes, Paula M; Chen Yu; Palmer, Richard E; Nikitin, Kirill; Fitzmaurice, Donald; Preece, Jon A

    2003-01-01

    This paper reviews recent experimental approaches to the development of surface nanostructures from nanoparticles. The formation of nanowires by electron beam writing in films of gold nanoparticles passivated with a specially designed class of ligand molecules (dialkyl sulfides) is presented, together with illustrations of practical nanostructures. Potential applications of this methodology are discussed. Another alternative to the controlled fabrication of arrays of nanoparticles, based on nanocrystals which contain molecular recognition elements in the ligand shell, is also surveyed. These particles aggregate in the presence of specifically designed molecular dications which act as a molecular binder. Finally, recent work on the formation of nanoscale surface architectures using x-ray patterning of self-assembled monolayers is introduced. Current and potential future applications of these surface nanostructures are discussed

  1. Mesoscopic quantum emitters coupled to plasmonic nanostructures

    DEFF Research Database (Denmark)

    Andersen, Mads Lykke

    for the spontaneous emission of mesoscopic quantum emitters is developed. The light-matter interaction is in this model modied beyond the dipole expectancy and found to both suppress and enhance the coupling to plasmonic modes in excellent agreement with our measurements. We demonstrate that this mesoscopic effect......This thesis reports research on quantum dots coupled to dielectric and plasmonic nano-structures by way of nano-structure fabrication, optical measurements, and theoretical modeling. To study light-matter interaction, plasmonic gap waveguides with nanometer dimensions as well as samples for studies...... to allow for e- cient plasmon-based single-photon sources. Theoretical studies of coupling and propagation properties of plasmonic waveguides reveal that a high-refractive index of the medium surrounding the emitter, e.g. nGaAs = 3.5, limits the realizability of ecient plasmon-based single-photon sources...

  2. Nanostructured piezoelectric energy harvesters

    CERN Document Server

    Briscoe, Joe

    2014-01-01

    This book covers a range of devices that use piezoelectricity to convert mechanical deformation into electrical energy and relates their output capabilities to a range of potential applications. Starting with a description of the fundamental principles and properties of piezo- and ferroelectric materials, where applications of bulk materials are well established, the book shows how nanostructures of these materials are being developed for energy harvesting applications. The authors show how a nanostructured device can be produced, and put in context some of the approaches that are being invest

  3. A four-probe thermal transport measurement method for nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li, E-mail: lishi@mail.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-04-15

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models.

  4. A four-probe thermal transport measurement method for nanostructures

    International Nuclear Information System (INIS)

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li

    2015-01-01

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models

  5. Modelling nanostructures with vicinal surfaces

    International Nuclear Information System (INIS)

    Mugarza, A; Schiller, F; Kuntze, J; Cordon, J; Ruiz-Oses, M; Ortega, J E

    2006-01-01

    Vicinal surfaces of the (111) plane of noble metals are characterized by free-electron-like surface states that scatter at one-dimensional step edges, making them ideal model systems to test the electronic properties of periodic lateral nanostructures. Here we use high-resolution, angle-resolved photoemission to analyse the evolution of the surface state on a variety of vicinal surface structures where both the step potential barrier and the superlattice periodicity can vary. A transition in the electron dimensionality is found as we vary the terrace size in single-phase step arrays. In double-phase, periodic faceted surfaces, we observe surface states that characterize each of the phases

  6. Epitaxial growth of hybrid nanostructures

    Science.gov (United States)

    Tan, Chaoliang; Chen, Junze; Wu, Xue-Jun; Zhang, Hua

    2018-02-01

    Hybrid nanostructures are a class of materials that are typically composed of two or more different components, in which each component has at least one dimension on the nanoscale. The rational design and controlled synthesis of hybrid nanostructures are of great importance in enabling the fine tuning of their properties and functions. Epitaxial growth is a promising approach to the controlled synthesis of hybrid nanostructures with desired structures, crystal phases, exposed facets and/or interfaces. This Review provides a critical summary of the state of the art in the field of epitaxial growth of hybrid nanostructures. We discuss the historical development, architectures and compositions, epitaxy methods, characterization techniques and advantages of epitaxial hybrid nanostructures. Finally, we provide insight into future research directions in this area, which include the epitaxial growth of hybrid nanostructures from a wider range of materials, the study of the underlying mechanism and determining the role of epitaxial growth in influencing the properties and application performance of hybrid nanostructures.

  7. Nanostructures-History

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Nanostructures-History. Inspiration to Nanotechnology-. The Japanese scientist Norio Taniguchi of the Tokyo University of Science was used the term "nano-technology" in a 1974 conference, to describe semiconductor processes such as thin film His definition was, ...

  8. Comparison of photobiomodulation therapy and suprascapular nerve-pulsed radiofrequency in chronic shoulder pain: a randomized controlled, single-blind, clinical trial.

    Science.gov (United States)

    Ökmen, Burcu Metin; Ökmen, Korgün

    2017-11-01

    Shoulder pain can be difficult to treat due to its complex anatomic structure, and different treatment methods can be used. We aimed to examine the efficacy of photobiomodulation therapy (PBMT) and suprascapular nerve (SSN)-pulsed radiofrequency (RF) therapy. In this prospective, randomized, controlled, single-blind study, 59 patients with chronic shoulder pain due to impingement syndrome received PBMT (group H) or SSN-pulsed RF therapy (group P) in addition to exercise therapy for 14 sessions over 2 weeks. Records were taken using visual analog scale (VAS), Shoulder Pain and Disability Index (SPADI), and Nottingham Health Profile (NHP) scoring systems for pretreatment (PRT), posttreatment (PST), and PST follow-up at months 1, 3, and 6. There was no statistically significant difference in initial VAS score, SPADI, and NHP values between group H and group P (p > 0.05). Compared to the values of PRT, PST, and PST at months 1, 3, and 6, VAS, SPADI, and NHP values were statistically significantly lower in both groups (p measurement times in VAS, SPADI, and NHP between the two groups. We established that PBMT and SSN-pulsed RF therapy are effective methods, in addition to exercise therapy, in patients with chronic shoulder pain. PBMT seems to be advantageous compared to SSN-pulsed RF therapy, as it is a noninvasive method.

  9. Synthesis and characterization of CuO flower-nanostructure processing by a domestic hydrothermal microwave

    International Nuclear Information System (INIS)

    Volanti, D.P.; Keyson, D.; Cavalcante, L.S.; Simoes, A.Z.; Joya, M.R.; Longo, E.; Varela, J.A.; Pizani, P.S.; Souza, A.G.

    2008-01-01

    The synthesis and characterization of CuO flower-nanostructure processed in domestic hydrothermal microwave oven was presented. Phase analysis was carried out using X-ray diffraction (XRD) and micro-Raman scattering (MRS) and the results confirmed the CuO flower-nanostructure as a single-phase. The field-emission scanning electron microscopy (FEG-SEM) was used to estimate the average spheres diameter while transmission electron microscope (TEM) to observe the thorn of the flower-nanostructures. The mechanism of CuO flower-nanostructures formation is proposed and explained

  10. Synthesis and characterization of CuO flower-nanostructure processing by a domestic hydrothermal microwave

    Energy Technology Data Exchange (ETDEWEB)

    Volanti, D.P. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Keyson, D. [Laboratorio de Ensino de Ciencias e Laboratorio de Combustiveis e Materiais, Departamento de Quimica, Universidade Federal da Paraiba, 58051-900 Joao Pessoa, PB (Brazil); Cavalcante, L.S. [Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil)], E-mail: laeciosc@bol.com.br; Simoes, A.Z. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Joya, M.R. [Departamento de Fisica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil); Longo, E.; Varela, J.A. [Laboratorio Interdisciplinar em Ceramica, Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP (Brazil); Pizani, P.S. [Departamento de Fisica, Universidade Federal de Sao Carlos, P.O. Box 676, 13565-905 Sao Carlos, SP (Brazil); Souza, A.G. [Laboratorio de Ensino de Ciencias e Laboratorio de Combustiveis e Materiais, Departamento de Quimica, Universidade Federal da Paraiba, 58051-900 Joao Pessoa, PB (Brazil)

    2008-07-14

    The synthesis and characterization of CuO flower-nanostructure processed in domestic hydrothermal microwave oven was presented. Phase analysis was carried out using X-ray diffraction (XRD) and micro-Raman scattering (MRS) and the results confirmed the CuO flower-nanostructure as a single-phase. The field-emission scanning electron microscopy (FEG-SEM) was used to estimate the average spheres diameter while transmission electron microscope (TEM) to observe the thorn of the flower-nanostructures. The mechanism of CuO flower-nanostructures formation is proposed and explained.

  11. 3D plasmonic nanostructures as building blocks for ultrasensitive Raman spectroscopy

    KAUST Repository

    Toma, Andrea; Chirumamilla, Manohar; Gopalakrishnan, Anisha; Das, Gobind; Proietti Zaccaria, Remo; Krahne, Roman; Rondanina, Eliana; Leoncini, Marco; Liberale, Carlo; De Angelis, Francesco De; Di Fabrizio, Enzo M.

    2014-01-01

    The fabrication of complex 3D plasmonic nanostructures opens new scenarios towards the realization of high electric field confinement and enhancement. We exploit the unique properties of these nanostructures for performing Raman spectroscopy in the single/few molecules detection limit. © 2014 OSA.

  12. Antibacterial Au nanostructured surfaces

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all

  13. Terahertz-field-induced photoluminescence of nanostructured gold films

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Malureanu, Radu; Zalkovskij, Maksim

    2013-01-01

    We experimentally demonstrate photoluminescence from nanostructured ultrathin gold films subjected to strong single-cycle terahertz transients with peak electric field over 300 kV/cm. We show that UV-Vis-NIR light is being generated and the efficiency of the process is strongly enhanced at the pe......We experimentally demonstrate photoluminescence from nanostructured ultrathin gold films subjected to strong single-cycle terahertz transients with peak electric field over 300 kV/cm. We show that UV-Vis-NIR light is being generated and the efficiency of the process is strongly enhanced...

  14. Precipitation synthesis and magnetic properties of self-assembled magnetite-chitosan nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bezdorozhev, Oleksii; Kolodiazhnyi, Taras; Vasylkiv, Oleg, E-mail: oleg.vasylkiv@nims.go.jp

    2017-04-15

    This paper reports the synthesis and magnetic properties of unique magnetite-chitosan nanostructures synthesized by the chemical precipitation of magnetite nanoparticles in the presence of chitosan. The influence of varying synthesis parameters on the morphology of the magnetic composites is determined. Depending on the synthesis parameters, magnetite-chitosan nanostructures of spherical (9–18 nm), rice-seed-like (75–290 nm) and lumpy (75–150 nm) shapes were obtained via self-assembly. Spherical nanostructures encapsulated by a 9–15 nm chitosan layer were assembled as well. The prospective morphology of the nanostructures is combined with their excellent magnetic characteristics. It was found that magnetite-chitosan nanostructures are ferromagnetic and pseudo-single domain. Rice-seed-like nanostructures exhibited a coercivity of 140 Oe and saturation magnetization of 56.7 emu/g at 300 K. However, a drop in the magnetic properties was observed for chitosan-coated spherical nanostructures due to the higher volume fraction of chitosan. - Highlights: • Magnetite-chitosan nanostructures are synthesized via self-assembly. • Different morphology can be obtained by adjusting the synthesis parameters. • An attractive combination of magnetic properties and morphology is obtained. • Magnetite-chitosan nanostructures are ferrimagnetic and pseudo-single domain.

  15. Precipitation synthesis and magnetic properties of self-assembled magnetite-chitosan nanostructures

    International Nuclear Information System (INIS)

    Bezdorozhev, Oleksii; Kolodiazhnyi, Taras; Vasylkiv, Oleg

    2017-01-01

    This paper reports the synthesis and magnetic properties of unique magnetite-chitosan nanostructures synthesized by the chemical precipitation of magnetite nanoparticles in the presence of chitosan. The influence of varying synthesis parameters on the morphology of the magnetic composites is determined. Depending on the synthesis parameters, magnetite-chitosan nanostructures of spherical (9–18 nm), rice-seed-like (75–290 nm) and lumpy (75–150 nm) shapes were obtained via self-assembly. Spherical nanostructures encapsulated by a 9–15 nm chitosan layer were assembled as well. The prospective morphology of the nanostructures is combined with their excellent magnetic characteristics. It was found that magnetite-chitosan nanostructures are ferromagnetic and pseudo-single domain. Rice-seed-like nanostructures exhibited a coercivity of 140 Oe and saturation magnetization of 56.7 emu/g at 300 K. However, a drop in the magnetic properties was observed for chitosan-coated spherical nanostructures due to the higher volume fraction of chitosan. - Highlights: • Magnetite-chitosan nanostructures are synthesized via self-assembly. • Different morphology can be obtained by adjusting the synthesis parameters. • An attractive combination of magnetic properties and morphology is obtained. • Magnetite-chitosan nanostructures are ferrimagnetic and pseudo-single domain.

  16. Ductility of Nanostructured Bainite

    Directory of Open Access Journals (Sweden)

    Lucia Morales-Rivas

    2016-12-01

    Full Text Available Nanostructured bainite is a novel ultra-high-strength steel-concept under intensive current research, in which the optimization of its mechanical properties can only come from a clear understanding of the parameters that control its ductility. This work reviews first the nature of this composite-like material as a product of heat treatment conditions. Subsequently, the premises of ductility behavior are presented, taking as a reference related microstructures: conventional bainitic steels, and TRIP-aided steels. The ductility of nanostructured bainite is then discussed in terms of work-hardening and fracture mechanisms, leading to an analysis of the three-fold correlation between ductility, mechanically-induced martensitic transformation, and mechanical partitioning between the phases. Results suggest that a highly stable/hard retained austenite, with mechanical properties close to the matrix of bainitic ferrite, is advantageous in order to enhance ductility.

  17. Hybrid phonons in nanostructures

    CERN Document Server

    Ridley, Brian K

    2017-01-01

    Crystalline semiconductor nanostructures have special properties associated with electrons and lattice vibrations and their interaction, and this is the topic of the book. The result of spatial confinement of electrons is indicated in the nomenclature of nonostructures: quantum wells, quantum wires, and quantum dots. Confinement also has a profound effect on lattice vibrations and an account of this is the prime focus. The documentation of the confinement of acoustic modes goes back to Lord Rayleigh’s work in the late nineteenth century, but no such documentation exists for optical modes. Indeed, it is only comparatively recently that any theory of the elastic properties of optical modes exists, and the account given in the book is comprehensive. A model of the lattice dynamics of the diamond lattice is given that reveals the quantitative distinction between acoustic and optical modes and the difference of connection rules that must apply at an interface. The presence of interfaces in nanostructures forces ...

  18. Nanostructured sulfur cathodes

    KAUST Repository

    Yang, Yuan

    2013-01-01

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

  19. Antibacterial Au nanostructured surfaces.

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-07

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.

  20. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  1. Semiconductors and semimetals nanostructured systems

    CERN Document Server

    Willardson, Robert K; Beer, Albert C; Reed, Mark A

    1992-01-01

    This is the first available volume to consolidate prominent topics in the emerging field of nanostructured systems. Recent technological advancements have led to a new era of nanostructure physics, allowing for the fabrication of nanostructures whose behavior is dominated by quantum interference effects. This new capability has enthused the experimentalist and theorist alike. Innumerable possibilities have now opened up for physical exploration and device technology on the nanoscale. This book, with contributions from five pioneering researchers, will allow the expert and novice alike to explore a fascinating new field.Provides a state-of-the-art review of quantum-scale artificially nanostructured electronic systemsIncludes contributions by world-known experts in the fieldOpens the field to the non-expert with a concise introductionFeatures discussions of:Low-dimensional condensed matter physicsProperties of nanostructured, ultrasmall electronic systemsMesoscopic physics and quantum transportPhysics of 2D ele...

  2. Peroxidases in nanostructures

    Directory of Open Access Journals (Sweden)

    Ana Maria eCarmona-Ribeiro

    2015-09-01

    Full Text Available Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting and reusability.

  3. Chiral silicon nanostructures

    International Nuclear Information System (INIS)

    Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

    2006-01-01

    Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

  4. Development of nanostructured protective "sight glasses" for IR gas sensors

    DEFF Research Database (Denmark)

    Bergmann, René; Davis, Zachary James; Schmidt, Michael Stenbæk

    2011-01-01

    In this work protective "sight glasses" for infrared gas sensors showing a sub-wavelength nanostructure with random patterns have been fabricated by reactive ion etching (RIE) in an easy and comparable cheap single step mask-less process. By an organic coating, the intrinsic water repellent...

  5. Iron filled carbon nanostructures from different precursors

    International Nuclear Information System (INIS)

    Costa, S.; Borowiak-Palen, E.; Bachmatiuk, A.; Ruemmeli, M.H.; Gemming, T.; Kalenczuk, R.J.

    2008-01-01

    Here, we present a study on the synthesis of different nanostructures with one single-step in situ filling (encapsulation) via carbon vapor deposition (CVD). Ferrocene, acetylferrocene and iron (II) nitrate as iron precursors were explored. The application of each of these compounds resulted in different carbon nanomaterials such as: iron filled multiwalled carbon nanotubes with a low filling ratio (Fe-MWCNT), iron filled nanocapsules and unfilled MWCNT. The as-produced samples were purified by high temperature annealing and acid treatment. The purified materials were characterised using transmission electron microscopy (TEM) and Raman spectroscopy

  6. Quantum Phase Extraction in Isospectral Electronic Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Christopher

    2010-04-28

    Quantum phase is not a direct observable and is usually determined by interferometric methods. We present a method to map complete electron wave functions, including internal quantum phase information, from measured single-state probability densities. We harness the mathematical discovery of drum-like manifolds bearing different shapes but identical resonances, and construct quantum isospectral nanostructures possessing matching electronic structure but divergent physical structure. Quantum measurement (scanning tunneling microscopy) of these 'quantum drums' [degenerate two-dimensional electron states on the Cu(111) surface confined by individually positioned CO molecules] reveals that isospectrality provides an extra topological degree of freedom enabling robust quantum state transplantation and phase extraction.

  7. Nanostructures by ion beams

    Science.gov (United States)

    Schmidt, B.

    Ion beam techniques, including conventional broad beam ion implantation, ion beam synthesis and ion irradiation of thin layers, as well as local ion implantation with fine-focused ion beams have been applied in different fields of micro- and nanotechnology. The ion beam synthesis of nanoparticles in high-dose ion-implanted solids is explained as phase separation of nanostructures from a super-saturated solid state through precipitation and Ostwald ripening during subsequent thermal treatment of the ion-implanted samples. A special topic will be addressed to self-organization processes of nanoparticles during ion irradiation of flat and curved solid-state interfaces. As an example of silicon nanocrystal application, the fabrication of silicon nanocrystal non-volatile memories will be described. Finally, the fabrication possibilities of nanostructures, such as nanowires and chains of nanoparticles (e.g. CoSi2), by ion beam synthesis using a focused Co+ ion beam will be demonstrated and possible applications will be mentioned.

  8. Shape control in wafer-based aperiodic 3D nanostructures

    International Nuclear Information System (INIS)

    Jeong, Hyeon-Ho; Mark, Andrew G; Gibbs, John G; Fischer, Peer; Reindl, Thomas; Waizmann, Ulrike; Weis, Jürgen

    2014-01-01

    Controlled local fabrication of three-dimensional (3D) nanostructures is important to explore and enhance the function of single nanodevices, but is experimentally challenging. We present a scheme based on e-beam lithography (EBL) written seeds, and glancing angle deposition (GLAD) grown structures to create nanoscale objects with defined shapes but in aperiodic arrangements. By using a continuous sacrificial corral surrounding the features of interest we grow isolated 3D nanostructures that have complex cross-sections and sidewall morphology that are surrounded by zones of clean substrate. (papers)

  9. Methods of fabricating nanostructures and nanowires and devices fabricated therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Arun; Shakouri, Ali; Sands, Timothy D.; Yang, Peidong; Mao, Samuel S.; Russo, Richard E.; Feick, Henning; Weber, Eicke R.; Kind, Hannes; Huang, Michael; Yan, Haoquan; Wu, Yiying; Fan, Rong

    2018-01-30

    One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as "nanowires", include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

  10. Fabrication of nanowires and nanostructures

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.; Piraux, L.

    2009-01-01

    We report on different approaches that we have adopted and developed for the fabrication of nanowires and nanostructures. Methods based on template synthesis and on self organization seem to be the most promising for the fabrication of nanomaterials and nanostructures due to their easiness and low...... cost. The development of a supported nanoporous alumina template and the possibility of using this template to combine electrochemical synthesis with lithographic methods open new ways for the fabrication of complex nanostructures. The numerous advantages of the supported template and its compatibility...

  11. Spectral investigations and DFT studies of 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione (caffeine) interaction and recognition by single amino acid derived self-assembled nanostructures

    Science.gov (United States)

    Govindhan, R.; Karthikeyan, B.

    2018-03-01

    Recognition of xanthine alkaloid caffeine with 3,5-bis(trifluoromethyl)benzylamine derived peptide nanotubes (BTTPNTs) through chemical interaction have been achieved through the host-guest like interaction. DFT simulation is carried out for caffeine interacted with BTTPNTs system and also experimentally characterized by ultraviolet-visible (UV-vis) absorbance, confocal Raman spectra (CRS) with microscopic imaging (CRM), FT-Raman, surface enhanced Raman scattering (SERS), UV-diffuse reflectance spectra (UV-DRS), high resolution transmission electron microscopy (HR-TEM) and cyclic voltammetry (CV) studies. The results are used to examine the morphologies, size of the nanostructure and study of its interaction with the caffeine molecule. The results show that BTTPNTs is having potential for sensing the caffeine molecules through the binding occurred from the NH2 of tyrosine moiety of the BTTPNTs. This intermolecular association through face-to-face stacking of BTTPNTs is explained by detailed DFT calculations.

  12. Nanostructure Engineered Chemical Sensors for Hazardous Gas and Vapor Detection

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2005-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxides nanowires or nanobelts, on a pair of interdigitated electrodes (IDE) processed with a silicon based microfabrication and micromachining technique. The IDE fingers were fabricated using thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to hazardous gases and vapors, such as acetone, benzene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing in our sensor platform can be understood by electron modulation between the nanostructure engineered device and gas molecules. As a result of the electron modulation, the conductance of nanodevice will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost.

  13. DNA origami compliant nanostructures with tunable mechanical properties.

    Science.gov (United States)

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2014-01-28

    DNA origami enables fabrication of precise nanostructures by programming the self-assembly of DNA. While this approach has been used to make a variety of complex 2D and 3D objects, the mechanical functionality of these structures is limited due to their rigid nature. We explore the fabrication of deformable, or compliant, objects to establish a framework for mechanically functional nanostructures. This compliant design approach is used in macroscopic engineering to make devices including sensors, actuators, and robots. We build compliant nanostructures by utilizing the entropic elasticity of single-stranded DNA (ssDNA) to locally bend bundles of double-stranded DNA into bent geometries whose curvature and mechanical properties can be tuned by controlling the length of ssDNA strands. We demonstrate an ability to achieve a wide range of geometries by adjusting a few strands in the nanostructure design. We further developed a mechanical model to predict both geometry and mechanical properties of our compliant nanostructures that agrees well with experiments. Our results provide a basis for the design of mechanically functional DNA origami devices and materials.

  14. Facile Synthesis and Tensile Behavior of TiO2 One-Dimensional Nanostructures

    Directory of Open Access Journals (Sweden)

    Li Shu-you

    2009-01-01

    Full Text Available Abstract High-yield synthesis of TiO2 one-dimensional (1D nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials, higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength are ~56.3 and 1.4 GPa, respectively.

  15. Formation of vertically aligned carbon nanostructures in plasmas: numerical modelling of growth and energy exchange

    Energy Technology Data Exchange (ETDEWEB)

    Denysenko, I; Azarenkov, N A, E-mail: idenysenko@yahoo.com [School of Physics and Technology, V N Karazin Kharkiv National University, 4 Svobody sq., 61077 Kharkiv (Ukraine)

    2011-05-04

    Results on modelling of the plasma-assisted growth of vertically aligned carbon nanostructures and of the energy exchange between the plasma and the growing nanostructures are reviewed. Growth of carbon nanofibres and single-walled carbon nanotubes is considered. Focus is made on studies that use the models based on mass balance equations for species, which are adsorbed on catalyst nanoparticles or walls of the nanostructures. It is shown that the models can be effectively used for the study and optimization of nanostructure growth in plasma-enhanced chemical vapour deposition. The results from these models are in good agreement with the available experimental data on the growth of nanostructures. It is discussed how input parameters for the models may be obtained.

  16. Electrons in Nanostructures

    DEFF Research Database (Denmark)

    Flindt, Christian

    2007-01-01

    in the possibilities o®ered by the quantum mechanical behavior of electrons when it comes to informa- tion processing. This branch of research is also concerned with fundamental questions in physics. Besides an introduction to the above-mentioned subjects, the thesis con- tains a number of contributions to the ¯elds...... of coherent electron manip- ulation and the statistical description of electron transport through nano- devices. The physics of the electrons are described with a combination of numerical methods, developed and applied in the thesis, and more analytical approaches, which are also discussed. The thesis......-based communication. The statistical description of electron transport through nanostructures is based on rate equations, and the primary contribution of the thesis in that respect is the development of a method that allows for the calculation of the distribution of electrons passing through a device. The method...

  17. Magnetism in carbon nanostructures

    CERN Document Server

    Hagelberg, Frank

    2017-01-01

    Magnetism in carbon nanostructures is a rapidly expanding field of current materials science. Its progress is driven by the wide range of applications for magnetic carbon nanosystems, including transmission elements in spintronics, building blocks of cutting-edge nanobiotechnology, and qubits in quantum computing. These systems also provide novel paradigms for basic phenomena of quantum physics, and are thus of great interest for fundamental research. This comprehensive survey emphasizes both the fundamental nature of the field, and its groundbreaking nanotechnological applications, providing a one-stop reference for both the principles and the practice of this emerging area. With equal relevance to physics, chemistry, engineering and materials science, senior undergraduate and graduate students in any of these subjects, as well as all those interested in novel nanomaterials, will gain an in-depth understanding of the field from this concise and self-contained volume.

  18. Nanostructured Photovoltaics for Space Power

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA NSTRF proposal entitled Nanostructured Photovoltaics for Space Power is targeted towards research to improve the current state of the art photovoltaic...

  19. Nanostructured Materials for Renewable Energy

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-11-01

    This factsheet describes a research project whose overall objective is to advance the fundamental understanding of novel photoelectronic organic device structures integrated with inorganic nanostructures, while also expanding the general field of nanomaterials for renewable energy devices and systems.

  20. Quantum Nanostructures by Droplet Epitaxy

    OpenAIRE

    Somsak Panyakeow

    2009-01-01

    Droplet epitaxy is an alternative growth technique for several quantum nanostructures. Indium droplets are distributed randomly on GaAs substrates at low temperatures (120-350'C). Under background pressure of group V elements, Arsenic and Phosphorous, InAs and InP nanostructures are created. Quantum rings with isotropic shape are obtained at low temperature range. When the growth thickness is increased, quantum rings are transformed to quantum dot rings. At high temperature range, anisotropic...

  1. Nanostructures via DNA scaffold metallization

    OpenAIRE

    Ning, C.; Zinchenko, A.; Baigl, D.; Pyshkina, O.; Sergeyev, V.; Endo, Kazunaka; Yoshikawa, K.

    2005-01-01

    The critical role of polymers in process of noble metals nanostructures formation is well known, however, the use of DNA chain template in this process is yet largely unknown. In this study we demonstrate different ways of silver deposition on DNA template and report the influence of silver nanostructures formation on DNA conformational state. Metallization of DNA chain proceeds by two different scenarios depending on DNA conformation. If DNA chain is unfolded (elongated) chain, silver reduct...

  2. Synthesis of vertically aligned metal oxide nanostructures

    KAUST Repository

    Roqan, Iman S.

    2016-03-03

    Metal oxide nanostructure and methods of making metal oxide nanostructures are provided. The metal oxide nanostructures can be 1 -dimensional nanostructures such as nanowires, nanofibers, or nanotubes. The metal oxide nanostructures can be doped or undoped metal oxides. The metal oxide nanostructures can be deposited onto a variety of substrates. The deposition can be performed without high pressures and without the need for seed catalysts on the substrate. The deposition can be performed by laser ablation of a target including a metal oxide and, optionally, a dopant. In some embodiments zinc oxide nanostructures are deposited onto a substrate by pulsed laser deposition of a zinc oxide target using an excimer laser emitting UV radiation. The zinc oxide nanostructure can be doped with a rare earth metal such as gadolinium. The metal oxide nanostructures can be used in many devices including light-emitting diodes and solar cells.

  3. Imaging of buried phosphorus nanostructures in silicon using scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, Lars [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); TOTAL Marketing Services, New Energies, La Défense 10, 92069 Paris La Défense Cedex (France); Reusch, Thilo C. G.; Hallam, Toby; Simmons, Michelle Y., E-mail: n.curson@ucl.ac.uk, E-mail: michelle.simmons@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Schofield, Steven R. [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); London Centre for Nanotechnology, UCL, London WC1H 0AH (United Kingdom); Department of Physics and Astronomy, UCL, London WC1E 6BT (United Kingdom); Curson, Neil J., E-mail: n.curson@ucl.ac.uk, E-mail: michelle.simmons@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); London Centre for Nanotechnology, UCL, London WC1H 0AH (United Kingdom); Department of Electronic and Electrical Engineering, UCL, London WC1E 7JE (United Kingdom)

    2014-06-23

    We demonstrate the locating and imaging of single phosphorus atoms and phosphorus dopant nanostructures, buried beneath the Si(001) surface using scanning tunneling microscopy. The buried dopant nanostructures have been fabricated in a bottom-up approach using scanning tunneling microscope lithography on Si(001). We find that current imaging tunneling spectroscopy is suited to locate and image buried nanostructures at room temperature and with residual surface roughness present. From these studies, we can place an upper limit on the lateral diffusion during encapsulation with low-temperature Si molecular beam epitaxy.

  4. Imaging of buried phosphorus nanostructures in silicon using scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Oberbeck, Lars; Reusch, Thilo C. G.; Hallam, Toby; Simmons, Michelle Y.; Schofield, Steven R.; Curson, Neil J.

    2014-01-01

    We demonstrate the locating and imaging of single phosphorus atoms and phosphorus dopant nanostructures, buried beneath the Si(001) surface using scanning tunneling microscopy. The buried dopant nanostructures have been fabricated in a bottom-up approach using scanning tunneling microscope lithography on Si(001). We find that current imaging tunneling spectroscopy is suited to locate and image buried nanostructures at room temperature and with residual surface roughness present. From these studies, we can place an upper limit on the lateral diffusion during encapsulation with low-temperature Si molecular beam epitaxy.

  5. Controlled synthesis of 2D Au nanostructure assembly with the assistance of sulfonated polyaniline nanotubes

    International Nuclear Information System (INIS)

    Yuan Junhua; Wang Zhijuan; Zhang Qixian; Han, Dongxue; Zhang Yuanjian; Shen Yanfei; Niu Li

    2006-01-01

    A wet chemical approach is used successfully to produce nanostructured Au material by the reduction of sulfonated polyaniline (SPANI) nanotubes. The Au nanostructures obtained are composed of single crystal Au nanoplates, which are aggregated layer-by-layer into stacks or edge-on-face into clusters at various conditions. The Au nanoplate diameter and thickness can be conveniently controlled in the range of 100 nm to 2 μm and 10 to 30 nm, respectively, with no accompanying single Au nanoparticles being observed. The formation of the Au nanostructures was controlled by the degradation of SPANI. The gradually and slowly released segments of SPANI served as the reductant during the growth of the 2D Au nanostructures

  6. The nanostructure problem

    International Nuclear Information System (INIS)

    Billinge, S.

    2010-01-01

    Diffraction techniques are making progress in tackling the difficult problem of solving the structures of nanoparticles and nanoscale materials. The great gift of x-ray crystallography has made us almost complacent in our ability to locate the three-dimensional coordinates of atoms in a crystal with a precision of around 10 -4 nm. However, the powerful methods of crystallography break down for structures in which order only extends over a few nanometers. In fact, as we near the one hundred year mark since the birth of crystallography, we face a resilient frontier in condensed matter physics: our inability to routinely and robustly determine the structure of complex nanostructured and amorphous materials. Knowing the structure and arrangement of atoms in a solid is so fundamental to understanding its properties that the topic routinely occupies the early chapters of every solid-state physics textbook. Yet what has become clear with the emergence of nanotechnology is that diffraction data alone may not be enough to uniquely solve the structure of nanomaterials. As part of a growing effort to incorporate the results of other techniques to constrain x-ray refinements - a method called 'complex modeling' which is a simple but elegant approach for combining information from spectroscopy with diffraction data to solve the structure of several amorphous and nanostructured materials. Crystallography just works, so we rarely question how and why this is so, yet understanding the physics of diffraction can be very helpful as we consider the nanostructure problem. The relationship between the electron density distribution in three dimensions (i.e., the crystal structure) and an x-ray diffraction pattern is well established: the measured intensity distribution in reciprocal space is the square of the Fourier transform of the autocorrelation function of the electron density distribution ρ(r). The fact that we get the autocorrelation function (rather than just the density

  7. Multiscale modelling of nanostructures

    International Nuclear Information System (INIS)

    Vvedensky, Dimitri D

    2004-01-01

    Most materials phenomena are manifestations of processes that are operative over a vast range of length and time scales. A complete understanding of the behaviour of materials thereby requires theoretical and computational tools that span the atomic-scale detail of first-principles methods and the more coarse-grained description provided by continuum equations. Recent efforts have focused on combining traditional methodologies-density functional theory, molecular dynamics, Monte Carlo methods and continuum descriptions-within a unified multiscale framework. This review covers the techniques that have been developed to model various aspects of materials behaviour with the ultimate aim of systematically coupling the atomistic to the continuum descriptions. The approaches described typically have been motivated by particular applications but can often be applied in wider contexts. The self-assembly of quantum dot ensembles will be used as a case study for the issues that arise and the methods used for all nanostructures. Although quantum dots can be obtained with all the standard growth methods and for a variety of material systems, their appearance is a quite selective process, involving the competition between equilibrium and kinetic effects, and the interplay between atomistic and long-range interactions. Most theoretical models have addressed particular aspects of the ordering kinetics of quantum dot ensembles, with far fewer attempts at a comprehensive synthesis of this inherently multiscale phenomenon. We conclude with an assessment of the current status of multiscale modelling strategies and highlight the main outstanding issues. (topical review)

  8. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima

    2016-07-26

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane\\'s water flux and solute retention. © 2016 The Royal Society of Chemistry.

  9. Nanostructured Basaltfiberconcrete Exploitational Characteristics

    Science.gov (United States)

    Saraykina, K. A.; Shamanov, V. A.

    2017-11-01

    The article demonstrates that the mass use of basalt fiber concrete (BFC) is constrained by insufficient study of their durability and serviceability in a variety of environments. This research is aimed at the study of the basalt fiber corrosion processes in the cement stone of BFC, the control of the new products structure formation in order to protect the reinforcing fiber from alkaline destruction and thereby improve the exploitational characteristics of the composite. The research result revealed that the modification of basaltfiber concrete by the dispersion of MWNTs contributes to the directional formation of new products in the cement matrix. The HAM additive in basaltfiberconcrete provides for the binding of portlandite to low-basic calcium hydroaluminosilicates, thus reducing the aggressive effect of the cement environment on the reinforcing fibers properties. The complex modification of BFC with nanostructured additives provides for an increase in its durability and exploitational properties (strength, frost resistance and water resistance) due to basalt fiber protection from alkali corrosion on account of the compacting of the contact zone “basalt fiber - cement stone” and designing of the new products structure and morphology of cement matrix over the fiber surface.

  10. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima; Sutisna, Burhannudin; Sougrat, Rachid; Nunes, Suzana Pereira

    2016-01-01

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane's water flux and solute retention. © 2016 The Royal Society of Chemistry.

  11. Characterization of ion beam induced nanostructures

    International Nuclear Information System (INIS)

    Ghatak, J.; Satpati, B.; Umananda, M.; Kabiraj, D.; Som, T.; Dev, B.N.; Akimoto, K.; Ito, K.; Emoto, T.; Satyam, P.V.

    2006-01-01

    Tailoring of nanostructures with energetic ion beams has become an active area of research leading to the fundamental understanding of ion-solid interactions at nanoscale regime and with possible applications in the near future. Rutherford backscattering spectrometry (RBS), high resolution transmission electron microscopy (HRTEM) and asymmetric X-ray Bragg-rocking curve experimental methods have been used to characterize ion-induced effects in nanostructures. The possibility of surface and sub-surface/interface alloying at nano-scale regime, ion-beam induced embedding, crater formation, sputtering yield variations for systems with isolated nanoislands, semi-continuous and continuous films of noble metals (Au, Ag) deposited on single crystalline silicon will be reviewed. MeV-ion induced changes in specified Au-nanoislands on silicon substrate are tracked as a function of ion fluence using ex situ TEM. Strain induced in the bulk silicon substrate surface due to 1.5 MeV Au 2+ and C 2+ ion beam irradiation is determined by using HRTEM and asymmetric Bragg X-ray rocking curve methods. Preliminary results on 1.5 MeV Au 2+ ion-induced effects in nanoislands of Co deposited on silicon substrate will be discussed

  12. Engineering Nano-Structured Multiferroic Thin Films

    Science.gov (United States)

    Cheung, Pui Lam

    Multiferroics exhibit remarkable tunabilities in their ferromagnetic, ferroelectric and magnetoelectric properties that provide the potential in enabling the control of magnetizations by electric field for the next generation non-volatile memories, antennas and motors. In recent research and developments in integrating single-phase ferroelectric and ferromagnetic materials, multiferroic composite demonstrated a promising magnetoelectric (ME) coupling for future applications. Atomic layer deposition (ALD) technique, on the other hand, allows fabrications of complex multiferroic nanostructures to investigate interfacial coupling between the two materials. In this work, radical-enhanced ALD of cobalt ferrite (CFO) and thermal ALD of lead zirconate titanate (PZT) were combined in fabricating complex multiferroic architectures in investigating the effect of nanostructuring and magnetic shape anisotropy on improving ME coupling. In particular, 1D CFO nanotubes and nanowires; 0D-3D CFO/PZT mesoporous composite; and 1D-1D CFO/PZT core-shell nanowire composite were studied. The potential implementation of nanostructured multiferroic composites into functioning devices was assessed by quantifying the converse ME coupling coefficient. The synthesis of 1D CFO nanostructures was realized by ALD of CFO in anodic aluminum oxide (AAO) membranes. This work provided a simple and inexpensive route to create parallel and high aspect ratio ( 55) magnetic nanostructures. The change in magnetic easy axis of (partially filled) CFO nanotubes from perpendicular to parallel in (fully-filled) nanowires indicated the significance of the geometric factor in controlling magnetizations and ME coupling. The 0D-3D CFO/PZT mesoporous composite demonstrated the optimizations of the strain transfer could be achieved by precise thickness control. 100 nm of mesoporous PZT was synthesized on Pt/TiOx/SiO2/Si using amphiphilic diblock copolymers as a porous ferroelectric template (10 nm pore diameter) for

  13. One-Dimensional Hetero-Nanostructures for Rechargeable Batteries.

    Science.gov (United States)

    Mai, Liqiang; Sheng, Jinzhi; Xu, Lin; Tan, Shuangshuang; Meng, Jiashen

    2018-04-17

    Rechargeable batteries are regarded as one of the most practical electrochemical energy storage devices that are able to convert and store the electrical energy generated from renewable resources, and they function as the key power sources for electric vehicles and portable electronics. The ultimate goals for electrochemical energy storage devices are high power and energy density, long lifetime, and high safety. To achieve the above goals, researchers have tried to apply various morphologies of nanomaterials as the electrodes to enhance the electrochemical performance. Among them, one-dimensional (1D) materials show unique superiorities, such as cross-linked structures for external stress buffering and large draw ratios for internal stress dispersion. However, a homogeneous single-component electrode material can hardly have the characteristics of high electronic/ionic conductivity and high stability in the electrochemical environment simultaneously. Therefore, designing well-defined functional 1D hetero-nanostructures that combine the advantages and overcome the limitations of different electrochemically active materials is of great significance. This Account summarizes fabrication strategies for 1D hetero-nanostructures, including nucleation and growth, deposition, and melt-casting and electrospinning. Besides, the chemical principles for each strategy are discussed. The nucleation and growth strategy is suitable for growing and constructing 1D hetero-nanostructures of partial transition metal compounds, and the experimental conditions for this strategy are relatively accessible. Deposition is a reliable strategy to synthesize 1D hetero-nanostructures by decorating functional layers on 1D substrate materials, on the condition that the preobtained substrate materials must be stable in the following deposition process. The melt-casting strategy, in which 1D hetero-nanostructures are synthesizes via a melting and molding process, is also widely used. Additionally

  14. Anodized ZnO nanostructures for photoelectrochemical water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Mao-Chia [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan (China); Wang, TsingHai [Department of Biomedical Engineering and Environment Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Wu, Bin-Jui [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan (China); Lin, Jing-Chie, E-mail: jclin4046@gmail.com [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan (China); Wu, Ching-Chen [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 310, Taiwan (China)

    2016-01-01

    Highlights: • ZnO nanostructures were synthesized by electrochemical anodic process. • The parameter of ZnO nanostructure was anodic potential. • The model of growth of ZnO nanostructure was investigated. - Abstract: Zinc oxide (ZnO) nanostructures were fabricated on the polished zinc foil by anodic deposition in an alkaline solution containing 1.0 M NaOH and 0.25 M Zn(NO{sub 3}){sub 2}. Potentiostatic anodization was conducted at two potentials (−0.7 V in the passive region and −1.0 V in the active region vs. SCE) which are higher than the open circuit potential (−1.03 V vs. SCE) and as-obtained ZnO nanostrcutures were investigated focusing on their structural, optical, electrical and photoelectrochemical (PEC) characteristics. All samples were confirmed ZnO by X-ray photoelectron spectroscopy and Raman spectra. Observations in the SEM images clearly showed that ZnO nanostructures prepared at −0.7 V vs. SCE were composed of nanowires at while those obtained at −1.0 V vs. SCE possessed nanosheets morphology. Result from transmission electron microscope and X-ray diffraction patterns suggested that the ZnO nanowires belonged to single crystalline with a preferred orientation of (0 0 2) whereas the ZnO nanosheets were polycrystalline. Following PEC experiments indicated that ZnO nanowires had higher photocurrent density of 0.32 mA/cm{sup 2} at 0.5 V vs. SCE under 100 mW/cm{sup 2} illumination. This value was about 1.9 times higher than that of ZnO nanosheets. Observed higher photocurrent was likely due to the single crystalline, preferred (0 0 2) orientation, higher carrier concentration and lower charge transfer resistance.

  15. Nanostructures for Organic Solar Cells

    DEFF Research Database (Denmark)

    Goszczak, Arkadiusz Jarosław

    2016-01-01

    The experimental work in this thesis is focused on the fabrication of nanostructures that can be implemented in organic solar cell (OSC) architecture for enhancement of the device performance. Solar devices made from organic material are gaining increased attention, compared to their inorganic...... counterparts, due to the promising advantages, such as transparency, flexibility, ease of processing etc. But their efficiencies cannot be compared to the inorganic ones. Boosting the efficiency of OSCs by nanopatterning has thus been puzzling many researchers within the past years. Therefore various methods...... have been proposed to be used for developing efficient nanostructures for OSC devices such as, plasmonic structures, nanowires (NWs), gratings, nanorods etc. The nanostructuring methods applied though, do not offer the possibility of a cheap, rapid, reproducible and scalable fabrication. It is the aim...

  16. Quantum Nanostructures by Droplet Epitaxy

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2009-02-01

    Full Text Available Droplet epitaxy is an alternative growth technique for several quantum nanostructures. Indium droplets are distributed randomly on GaAs substrates at low temperatures (120-350'C. Under background pressure of group V elements, Arsenic and Phosphorous, InAs and InP nanostructures are created. Quantum rings with isotropic shape are obtained at low temperature range. When the growth thickness is increased, quantum rings are transformed to quantum dot rings. At high temperature range, anisotropic strain gives rise to quantum rings with square holes and non-uniform ring stripe. Regrowth of quantum dots on these anisotropic quantum rings, Quadra-Quantum Dots (QQDs could be realized. Potential applications of these quantum nanostructures are also discussed.

  17. Interfacing nanostructures to biological cells

    Science.gov (United States)

    Chen, Xing; Bertozzi, Carolyn R.; Zettl, Alexander K.

    2012-09-04

    Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated .alpha.-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the .alpha.-N-acetylgalactosamine groups on the nanostructure.

  18. PREFACE: Self-organized nanostructures

    Science.gov (United States)

    Rousset, Sylvie; Ortega, Enrique

    2006-04-01

    In order to fabricate ordered arrays of nanostructures, two different strategies might be considered. The `top-down' approach consists of pushing the limit of lithography techniques down to the nanometre scale. However, beyond 10 nm lithography techniques will inevitably face major intrinsic limitations. An alternative method for elaborating ultimate-size nanostructures is based on the reverse `bottom-up' approach, i.e. building up nanostructures (and eventually assemble them to form functional circuits) from individual atoms or molecules. Scanning probe microscopies, including scanning tunnelling microscopy (STM) invented in 1982, have made it possible to create (and visualize) individual structures atom by atom. However, such individual atomic manipulation is not suitable for industrial applications. Self-assembly or self-organization of nanostructures on solid surfaces is a bottom-up approach that allows one to fabricate and assemble nanostructure arrays in a one-step process. For applications, such as high density magnetic storage, self-assembly appears to be the simplest alternative to lithography for massive, parallel fabrication of nanostructure arrays with regular sizes and spacings. These are also necessary for investigating the physical properties of individual nanostructures by means of averaging techniques, i.e. all those using light or particle beams. The state-of-the-art and the current developments in the field of self-organization and physical properties of assembled nanostructures are reviewed in this issue of Journal of Physics: Condensed Matter. The papers have been selected from among the invited and oral presentations of the recent summer workshop held in Cargese (Corsica, France, 17-23 July 2005). All authors are world-renowned in the field. The workshop has been funded by the Marie Curie Actions: Marie Curie Conferences and Training Courses series named `NanosciencesTech' supported by the VI Framework Programme of the European Community, by

  19. Zinc stannate nanostructures: hydrothermal synthesis

    International Nuclear Information System (INIS)

    Baruah, Sunandan; Dutta, Joydeep

    2011-01-01

    Nanostructured binary semiconducting metal oxides have received much attention in the last decade owing to their unique properties rendering them suitable for a wide range of applications. In the quest to further improve the physical and chemical properties, an interest in ternary complex oxides has become noticeable in recent times. Zinc stannate or zinc tin oxide (ZTO) is a class of ternary oxides that are known for their stable properties under extreme conditions, higher electron mobility compared to its binary counterparts and other interesting optical properties. The material is thus ideal for applications from solar cells and sensors to photocatalysts. Among the different methods of synthesizing ZTO nanostructures, the hydrothermal method is an attractive green process that is carried out at low temperatures. In this review, we summarize the conditions leading to the growth of different ZTO nanostructures using the hydrothermal method and delve into a few of its applications reported in the literature. (topical review)

  20. Electrical Modulation of Fano Resonance in Plasmonic Nanostructures Using Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Kildishev, Alexander V.

    2014-01-01

    Pauli blocking of interband transistions gives rise to tunable optical properties in single layer graphene (SLG). This effect is exploited in a graphene-nanoantenna hybrid device where Fano resonant plasmonic nanostructures are fabricated on top of a graphene sheet. The use of Fano resonant eleme......-element simulations. Our approach can be used for development of next generation of tunable plasmonic and hybrid nanophotonic devices.......Pauli blocking of interband transistions gives rise to tunable optical properties in single layer graphene (SLG). This effect is exploited in a graphene-nanoantenna hybrid device where Fano resonant plasmonic nanostructures are fabricated on top of a graphene sheet. The use of Fano resonant...... elements enhances the interaction of incident radiation with the graphene sheet and enables efficient electrical modulation of the plasmonic resonance. We observe electrically controlled damping in the Fano resonances occurring at approximately 2 μm, and the results are verified by full-wave 3D finite...

  1. Vortex ice in nanostructured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Libal, Andras J [Los Alamos National Laboratory

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  2. Formation mechanism of PbTe dendritic nanostructures grown by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sangwoo; Kim, Hyunghoon; Lee, Ho Seong, E-mail: hs.lee@knu.ac.kr

    2017-02-01

    The formation mechanism of PbTe dendritic nanostructures grown at room temperature by electrodeposition in nitric acid electrolytes containing Pb and Te was investigated. Scanning electron microscopy and transmission electron microscopy analyses indicated that the PbTe dendritic nanostructures were composed of triangular-shaped units surrounded by {111} and {110} planes. Because of the interfacial energy anisotropy of the {111} and {110} planes and the difference in the current density gradient, the growth rate in the vertical direction of the (111) basal plane was slower than that in the direction of the tip of the triangular shape, leading to growth in the tip direction. In contrast to the general growth direction of fcc dendrites, namely <100>, the tip direction of the {111} basal plane for our samples was <112>, and the PbTe dendritic nanostructures grew in the tip direction. The angles formed by the main trunk and first branches were regular and approximately 60°, and those between the first and second branches were also approximately 60°. Finally, the nanostructures grew in single-crystalline dendritic form. - Highlights: • PbTe dendrite nanostructures were grown by electrodeposition. • PbTe dendritic nanostructures were composed of triangular-shaped units. • The formation mechanism of PbTe dendrite nanostructures was characterized.

  3. Preparation and characterization of CuO nanostructures on copper substrate as selective solar absorbers

    International Nuclear Information System (INIS)

    Karthick Kumar, S.; Murugesan, S.; Suresh, S.

    2014-01-01

    Selective solar absorber coatings of copper oxide (CuO) on copper substrates are prepared by room temperature oxidation of copper at different alkaline conditions. The surface morphology and structural analyses of the CuO coatings are carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectroscopy techniques. XRD and Raman studies indicated the single phase nature and high crystallinity of the prepared CuO nanostructures. Different CuO nanostructures, viz., nanoneedles, nanofibers and nanoparticles are formed at different alkaline conditions. The influence of reaction time on morphology of the CuO nanostructures is also studied. The thermal emittance values of these nanostructured CuO samples are found to be in the range of 6–7% and their solar absorptances are ranged between 84 and 90%. The observed high solar selectivity values (>12.7) suggest that these coatings can be used as selective absorbers in solar thermal gadgets. - Highlights: • Nanostructured CuO thin films on Cu substrate have been prepared by a facile method. • Morphology of the CuO nanostructures varies with reaction pH. • The thin films show high absorptance in the visible region and low thermal emittance. • Multiple absorption in the porous structure leads to high solar absorptance. • Nanostructures posses solar selectivity values >12

  4. The generalized Shockley-Queisser limit for nanostructured solar cells

    Science.gov (United States)

    Xu, Yunlu; Gong, Tao; Munday, Jeremy N.

    2015-09-01

    The Shockley-Queisser limit describes the maximum solar energy conversion efficiency achievable for a particular material and is the standard by which new photovoltaic technologies are compared. This limit is based on the principle of detailed balance, which equates the photon flux into a device to the particle flux (photons or electrons) out of that device. Nanostructured solar cells represent a novel class of photovoltaic devices, and questions have been raised about whether or not they can exceed the Shockley-Queisser limit. Here we show that single-junction nanostructured solar cells have a theoretical maximum efficiency of ˜42% under AM 1.5 solar illumination. While this exceeds the efficiency of a non-concentrating planar device, it does not exceed the Shockley-Queisser limit for a planar device with optical concentration. We consider the effect of diffuse illumination and find that with optical concentration from the nanostructures of only × 1,000, an efficiency of 35.5% is achievable even with 25% diffuse illumination. We conclude that nanostructured solar cells offer an important route towards higher efficiency photovoltaic devices through a built-in optical concentration.

  5. Towards highly sensitive strain sensing based on nanostructured materials

    International Nuclear Information System (INIS)

    Dao, Dzung Viet; Nakamura, Koichi; Sugiyama, Susumu; Bui, Tung Thanh; Dau, Van Thanh; Yamada, Takeo; Hata, Kenji

    2010-01-01

    This paper presents our recent theoretical and experimental study of piezo-effects in nanostructured materials for highly sensitive, high resolution mechanical sensors. The piezo-effects presented here include the piezoresistive effect in a silicon nanowire (SiNW) and single wall carbon nanotube (SWCNT) thin film, as well as the piezo-optic effect in a Si photonic crystal (PhC) nanocavity. Firstly, the electronic energy band structure of the silicon nanostructure is discussed and simulated by using the First-Principles Calculations method. The result showed a remarkably different energy band structure compared with that of bulk silicon. This difference in the electronic state will result in different physical, chemical, and therefore, sensing properties of silicon nanostructures. The piezoresistive effects of SiNW and SWCNT thin film were investigated experimentally. We found that, when the width of ( 110 ) p-type SiNW decreases from 500 to 35 nm, the piezoresistive effect increases by more than 60%. The longitudinal piezoresistive coefficient of SWCNT thin film was measured to be twice that of bulk p-type silicon. Finally, theoretical investigations of the piezo-optic effect in a PhC nanocavity based on Finite Difference Time Domain (FDTD) showed extremely high resolution strain sensing. These nanostructures were fabricated based on top-down nanofabrication technology. The achievements of this work are significant for highly sensitive, high resolution and miniaturized mechanical sensors

  6. Computer Code for Nanostructure Simulation

    Science.gov (United States)

    Filikhin, Igor; Vlahovic, Branislav

    2009-01-01

    Due to their small size, nanostructures can have stress and thermal gradients that are larger than any macroscopic analogue. These gradients can lead to specific regions that are susceptible to failure via processes such as plastic deformation by dislocation emission, chemical debonding, and interfacial alloying. A program has been developed that rigorously simulates and predicts optoelectronic properties of nanostructures of virtually any geometrical complexity and material composition. It can be used in simulations of energy level structure, wave functions, density of states of spatially configured phonon-coupled electrons, excitons in quantum dots, quantum rings, quantum ring complexes, and more. The code can be used to calculate stress distributions and thermal transport properties for a variety of nanostructures and interfaces, transport and scattering at nanoscale interfaces and surfaces under various stress states, and alloy compositional gradients. The code allows users to perform modeling of charge transport processes through quantum-dot (QD) arrays as functions of inter-dot distance, array order versus disorder, QD orientation, shape, size, and chemical composition for applications in photovoltaics and physical properties of QD-based biochemical sensors. The code can be used to study the hot exciton formation/relation dynamics in arrays of QDs of different shapes and sizes at different temperatures. It also can be used to understand the relation among the deposition parameters and inherent stresses, strain deformation, heat flow, and failure of nanostructures.

  7. Thermoelectric effects in magnetic nanostructures

    NARCIS (Netherlands)

    Hatami, Moosa; Bauer, Gerrit E.W.; Zhang, Q.F.; Kelly, Paul J.

    2009-01-01

    We model and evaluate the Peltier and Seebeck effects in magnetic multilayer nanostructures by a finite-element theory of thermoelectric properties. We present analytical expressions for the thermopower and the current-induced temperature changes due to Peltier cooling/heating. The thermopower of a

  8. Noncollinear magnetism in manganese nanostructures

    Czech Academy of Sciences Publication Activity Database

    Zelený, Martin; Šob, Mojmír; Hafner, J.

    2009-01-01

    Roč. 80, č. 14 (2009), 144414/1-144414/19 ISSN 1098-0121 R&D Projects: GA AV ČR IAA100100920; GA MŠk OC09011 Institutional research plan: CEZ:AV0Z20410507 Keywords : magnetism of nanostructures * nanowires * noncollinear magnetism * manganese Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

  9. A Review on the Low-Dimensional and Hybridized Nanostructured Diamond Films

    Directory of Open Access Journals (Sweden)

    Hongdong Li

    2015-01-01

    Full Text Available In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.

  10. Semi-automated quantification of living cells with internalized nanostructures

    KAUST Repository

    Margineanu, Michael B.

    2016-01-15

    Background Nanostructures fabricated by different methods have become increasingly important for various applications in biology and medicine, such as agents for medical imaging or cancer therapy. In order to understand their interaction with living cells and their internalization kinetics, several attempts have been made in tagging them. Although methods have been developed to measure the number of nanostructures internalized by the cells, there are only few approaches aimed to measure the number of cells that internalize the nanostructures, and they are usually limited to fixed-cell studies. Flow cytometry can be used for live-cell assays on large populations of cells, however it is a single time point measurement, and does not include any information about cell morphology. To date many of the observations made on internalization events are limited to few time points and cells. Results In this study, we present a method for quantifying cells with internalized magnetic nanowires (NWs). A machine learning-based computational framework, CellCognition, is adapted and used to classify cells with internalized and no internalized NWs, labeled with the fluorogenic pH-dependent dye pHrodo™ Red, and subsequently to determine the percentage of cells with internalized NWs at different time points. In a “proof-of-concept”, we performed a study on human colon carcinoma HCT 116 cells and human epithelial cervical cancer HeLa cells interacting with iron (Fe) and nickel (Ni) NWs. Conclusions This study reports a novel method for the quantification of cells that internalize a specific type of nanostructures. This approach is suitable for high-throughput and real-time data analysis and has the potential to be used to study the interaction of different types of nanostructures in live-cell assays.

  11. Synthesis and magnetic properties of superparamagnetic CoAs nanostructures

    Science.gov (United States)

    Desai, P.; Ashokaan, N.; Masud, J.; Pariti, A.; Nath, M.

    2015-03-01

    This article provides a comprehensive guide on the synthesis and characterization of superparamagnetic CoAs nanoparticles and elongated nanostructures with high blocking temperature, (TB), via hot-injection precipitation and solvothermal methods. Cobalt arsenides constitute an important family of magnetically active solids that find a variety of applications ranging from magnetic semiconductors to biomedical imaging. While the higher temperature hot-injection precipitation technique (300 °C) yields pure CoAs nanostructures, the lower temperature solvothermal method (200 °C) yields a mixture of CoAs nanoparticles along with other Co-based impurity phases. The synthesis in all these cases involved usage of triphenylarsine ((C6H5)3As) as the As precursor which reacts with solid Co2(CO)8 by ligand displacement to yield a single source precursor. The surfactant, hexadecylamine (HDA) further assists in controlling the morphology of the nanostructures. HDA also provides a basic medium and molten flux-like conditions for the redox chemistry to occur between Co and As at elevated temperatures. The influence of the length of reaction time was investigated by studying the evolution of product morphology over time. It was observed that while spontaneous nucleation at higher temperature followed by controlled growth led to the predominant formation of short nanorods, with longer reaction time, the nanorods were further converted to nanoparticles. The size of the nanoparticles obtained, was mostly in the range of 10-15 nm. The key finding of this work is exceptionally high coercivity in CoAs nanostructures for the first time. Coercivity observed was as high as 0.1 T (1000 Oe) at 2 K. These kinds of magnetic nanostructures find multiple applications in spintronics, whereas the superparamagnetic nanoparticles are viable for use in magnetic storage, ferrofluids and as contrast enhancing agents in MRI.

  12. Fabrication of zein nanostructure

    Science.gov (United States)

    Luecha, Jarupat

    resins. The soft lithography technique was mainly used to fabricate micro and nanostructures on zein films. Zein material well-replicated small structures with the smallest size at sub micrometer scale that resulted in interesting photonic properties. The bonding method was also developed for assembling portable zein microfluidic devices with small shape distortion. Zein-zein and zein-glass microfluidic devices demonstrated sufficient strength to facilitate fluid flow in a complex microfluidic design with no leakage. Aside from the fabrication technique development, several potential applications of this environmentally friendly microfluidic device were investigated. The concentration gradient manipulation of Rhodamine B solution in zein-glass microfluidic devices was demonstrated. The diffusion of small molecules such as fluorescent dye into the wall of the zein microfluidic channels was observed. However, with this formulation, zein microfluidic devices were not suitable for cell culture applications. This pioneer study covered a wide spectrum of the implementation of the two nanotechnology approaches to advance zein biomaterial which provided proof of fundamental concepts as well as presenting some limitations. The findings in this study can lead to several innovative research opportunities of advanced zein biomaterials with broad applications. The information from the study of zein nanocomposite structure allows the packaging industry to develop the low cost biodegradable materials with physical property improvement. The information from the study of the zein microfluidic devices allows agro-industry to develop the nanotechnology-enabled microfluidic sensors fabricated entirely from biodegradable polymer for on-site disease or contaminant detection in the fields of food and agriculture.

  13. Space Surveillance Network (SSN) Optical Augmentation (SOA)

    Science.gov (United States)

    1999-04-01

    physical characteristics, and the geocentric and topocentric positions of each satellite in the deep space object catalog. The SKYMAP propagator...maintains the geocentric and topocentric positions and recomputes the position of each object several times a minute. For each scheduling...AINTENANCE Mission Personnel ( Staffing ) Officers 0.0 0.0 0.0 0.0 $90K/person (0) Enlisted 0.0 0.0 0.0 0.0 $45K/person (0) Contractor 20.0

  14. Molecular dynamics simulation of carbon nanostructures: The C60 buckminsterfullerene

    International Nuclear Information System (INIS)

    Laszlo, Istvan; Zsoldos, Ibolya

    2012-01-01

    Molecular dynamics calculations can reveal the physical and chemical properties of various carbon nanostructures or can help to devise the possible formation pathways. In our days the most well-known carbon nanostructures are the fullerenes, the nanotubes, and the graphene. The fullerenes and nanotubes can be thought of as being formed from graphene sheets, i.e., single layers of carbon atoms arranged in a honeycomb lattice. Usually the nature does not follow the mathematical constructions. Although the first time the C 60 and the C 70 were produced by laser irradiated graphite, the fullerene formation theories are based on various fragments of carbon chains and networks of pentagonal and hexagonal rings. In the present article various formation pathways for the buckminsterfullerene C 60 molecule will be presented. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Ternary oxide nanostructures and methods of making same

    Science.gov (United States)

    Wong, Stanislaus S [Stony Brook, NY; Park, Tae-Jin [Port Jefferson, NY

    2009-09-08

    A single crystalline ternary nanostructure having the formula A.sub.xB.sub.yO.sub.z, wherein x ranges from 0.25 to 24, and y ranges from 1.5 to 40, and wherein A and B are independently selected from the group consisting of Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Ce, Cl, Cm, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Tc, Te, Ti, Tl, Tm, U, V, W, Y, Yb, and Zn, wherein the nanostructure is at least 95% free of defects and/or dislocations.

  16. Direct writing of metal nanostructures: lithographic tools for nanoplasmonics research.

    Science.gov (United States)

    Leggett, Graham J

    2011-03-22

    Continued progress in the fast-growing field of nanoplasmonics will require the development of new methods for the fabrication of metal nanostructures. Optical lithography provides a continually expanding tool box. Two-photon processes, as demonstrated by Shukla et al. (doi: 10.1021/nn103015g), enable the fabrication of gold nanostructures encapsulated in dielectric material in a simple, direct process and offer the prospect of three-dimensional fabrication. At higher resolution, scanning probe techniques enable nanoparticle particle placement by localized oxidation, and near-field sintering of nanoparticulate films enables direct writing of nanowires. Direct laser "printing" of single gold nanoparticles offers a remarkable capability for the controlled fabrication of model structures for fundamental studies, particle-by-particle. Optical methods continue to provide a powerful support for research into metamaterials.

  17. Development of Nanostructured Austempered Ductile Cast Iron

    Science.gov (United States)

    Panneerselvam, Saranya

    Austempered Ductile Cast Iron is emerging as an important engineering materials in recent years because of its excellent combination of mechanical properties such as high strength with good ductility, good fatigue strength and fracture toughness together with excellent wear resistance. These combinations of properties are achieved by the microstructure consisting of acicular ferrite and high carbon austenite. Refining of the ausferritic microstructure will further enhance the mechanical properties of ADI and the presence of proeutectoid ferrite in the microstructure will considerably improve the ductility of the material. Thus, the focus of this investigation was to develop nanostructured austempered ductile cast iron (ADI) consisting of proeutectoid ferrite, bainitic ferrite and high carbon austenite and to determine its microstructure-property relationships. Compact tension and cylindrical tensile test samples were prepared as per ASTM standards, subjected to various heat treatments and the mechanical tests including the tensile tests, plane strain fracture toughness tests, hardness tests were performed as per ASTM standards. Microstructures were characterized by optical metallography, X-ray diffraction, SEM and TEM. Nanostructured ADI was achieved by a unique heat treatment consisting of austenitization at a high temperature and subsequent plastic deformation at the same austenitizing temperature followed by austempering. The investigation also examined the effect of cryogenic treatment, effect of intercritical austenitizing followed by single and two step austempering, effect of high temperature plastic deformation on the microstructure and mechanical properties of the low alloyed ductile cast iron. The mechanical and thermal stability of the austenite was also investigated. An analytical model has been developed to understand the crack growth process associated with the stress induced transformation of retained austenite to martensite.

  18. Chemical Sensors Based on Metal Oxide Nanostructures

    Science.gov (United States)

    Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

    2006-01-01

    This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

  19. Composite materials formed with anchored nanostructures

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  20. Pressure effects on nanostructured manganites

    International Nuclear Information System (INIS)

    Acha, C.; Garbarino, G.; Leyva, A.G.

    2007-01-01

    We have measured the pressure sensitivity of magnetic properties on La 5/8-y Pr y Ca 3/8 MnO 3 (y=0.3) nanostructured powders. Samples were synthesized following a microwave assisted denitration process and a final heat treatment at different temperatures to control the grain size of the samples. A span in grain diameters from 40 nm to ∼1000 nm was obtained. Magnetization curves as a function of temperature were measured following different thermomagnetic histories. AC susceptibility as a function of temperature was also measured at different hydrostatic pressures (up to 10 kbar) and for different frequencies. Our results indicate that the nanostructuration plays a role of an internal pressure, producing a structural deformation with similar effects to those obtained under an external hydrostatic pressure

  1. Imaging edges of nanostructured graphene

    DEFF Research Database (Denmark)

    Kling, Jens; Cagliani, Alberto; Booth, T. J.

    Graphene, as the forefather of 2D-materials, attracts much attention due to its extraordinary properties like transparency, flexibility and outstanding high conductivity, together with a thickness of only one atom. However, graphene also possesses no band gap, which makes it unsuitable for many...... electronic applications like transistors. It has been shown theoretically that by nanostructuring pristine graphene, e.g. with regular holes, the electronic properties can be tuned and a band gap introduced. The size, distance and edge termination of these “defects” influence the adaptability....... Such nanostructuring can be done experimentally, but especially characterization at atomic level is a huge challenge. High-resolution TEM (HRTEM) is used to characterize the atomic structure of graphene. We optimized the imaging conditions used for the FEI Titan ETEM. To reduce the knock-on damage of the carbon atoms...

  2. Nanostructured materials for water desalination

    Energy Technology Data Exchange (ETDEWEB)

    Humplik, T; Lee, J; O' Hern, S C; Fellman, B A; Karnik, R; Wang, E N [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge (United States); Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T, E-mail: tlaoui@kfupm.edu.sa, E-mail: karnik@mit.edu, E-mail: enwang@mit.edu [Departments of Mechanical Engineering and Chemical Engineering and Research Institute, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2011-07-22

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity. (topical review)

  3. Nanostructured materials for water desalination

    International Nuclear Information System (INIS)

    Humplik, T; Lee, J; O'Hern, S C; Fellman, B A; Karnik, R; Wang, E N; Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T

    2011-01-01

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity. (topical review)

  4. Nanostructured materials for water desalination

    Science.gov (United States)

    Humplik, T.; Lee, J.; O'Hern, S. C.; Fellman, B. A.; Baig, M. A.; Hassan, S. F.; Atieh, M. A.; Rahman, F.; Laoui, T.; Karnik, R.; Wang, E. N.

    2011-07-01

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

  5. Reactor casts light on nanostructures

    International Nuclear Information System (INIS)

    Garvey, C.

    2002-01-01

    Chris Garvey explains how the replacement research reactor will help scientists to design better materials by understanding how macromolecules behave. Australia is making a substantial financial commitment to providing scientists with facilities to scatter neutrons. Neutron scattering is one of the core areas of science in which the Australian Nuclear Science and Technology Organisation (ANSTO) invests its resources. His particular interest is to find out the way nature uses macromolecules, and how the shape and interaction of macromolecules with other molecules change their function. Biologists call aggregates of macromolecules, 'nanostructures'. Neutron probes are used at ANSTO for studying nanostructures, and in particular the organisation of the protein that is used to transport oxygen in the blood. Small angle neutron scattering was also allowed to understand at microscopic level, how humidity changes the mechanical properties of fibres

  6. Fibrin nanostructures for biomedical applications

    Czech Academy of Sciences Publication Activity Database

    Riedelová-Reicheltová, Zuzana; Brynda, Eduard; Riedel, Tomáš

    2016-01-01

    Roč. 65, Suppl. 2 (2016), S263-S272 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 Keywords : fibrinogen * fibrin-bound thrombin * nanostructures Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S263.pdf

  7. Nanotechnologies. Properties and applications of nanostructured materials

    International Nuclear Information System (INIS)

    Rempel, A A

    2007-01-01

    The review summarises the main methods for the preparation of nanostructured metals, alloys, semiconductors and ceramics. The formation mechanisms of nanostructures based on two different principles, viz. the assembly principle (bottom-up) and the disintegration principle (top-down), are analysed. Isolated nanoparticles, nanopowders and compact nanomaterials produced by these methods possess different properties. The scope of application of various classes of nanostructured materials is considered and the topicality of the development of nanoindustry is emphasised.

  8. Metal chalcogenide nanostructures for renewable energy applications

    CERN Document Server

    Qurashi, Ahsanulhaq

    2014-01-01

    This first ever reference book that focuses on metal chalcogenide semiconductor nanostructures for renewable energy applications encapsulates the state-of-the-art in multidisciplinary research on the metal chalcogenide semiconductor nanostructures (nanocrystals, nanoparticles, nanorods, nanowires,  nanobelts, nanoflowers, nanoribbons and more).  The properties and synthesis of a class of nanomaterials is essential to renewable energy manufacturing and this book focuses on the synthesis of metal chalcogendie nanostructures, their growth mechanism, optical, electrical, and other important prop

  9. Reactor and method for production of nanostructures

    Science.gov (United States)

    Sunkara, Mahendra Kumar; Kim, Jeong H.; Kumar, Vivekanand

    2017-04-25

    A reactor and method for production of nanostructures, including metal oxide nanowires or nanoparticles, are provided. The reactor includes a regulated metal powder delivery system in communication with a dielectric tube; a plasma-forming gas inlet, whereby a plasma-forming gas is delivered substantially longitudinally into the dielectric tube; a sheath gas inlet, whereby a sheath gas is delivered into the dielectric tube; and a microwave energy generator coupled to the dielectric tube, whereby microwave energy is delivered into a plasma-forming gas. The method for producing nanostructures includes providing a reactor to form nanostructures and collecting the formed nanostructures, optionally from a filter located downstream of the dielectric tube.

  10. Is there a shift to 'active nanostructures'?

    International Nuclear Information System (INIS)

    Subramanian, Vrishali; Youtie, Jan; Porter, Alan L.; Shapira, Philip

    2010-01-01

    It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure 'changes or evolves its state during its operation,' according to the National Science Foundation's (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a 'shift' to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.

  11. Is there a shift to "active nanostructures"?

    Science.gov (United States)

    Subramanian, Vrishali; Youtie, Jan; Porter, Alan L.; Shapira, Philip

    2010-01-01

    It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure "changes or evolves its state during its operation," according to the National Science Foundation's (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a "shift" to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.

  12. Transparent Conductive Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-06-22

    The objectives of this program between UT-Battelle, LLC (the ''Contractor'') and (Battelle Memorial Institute) (the "Participant") were directed towards achieving significant improvement: in the electrical conductivity and optical/infrared transmission of single-wall carbon nanotube (SWNT)-based composite materials. These materials will be used in coating applications that range from aircraft canopies to display applications. The goal of the project was to obtain supported mats of SWNTs with sheet conductivities approaching 10 ohms/square combined with high optical transmission (>85% transmission at 550 nm), thereby permitting their application as a replacement for indium tin oxide (ITO) in a variety of applications such as flexible displays.

  13. Semiconductor quantum optics with tailored photonic nanostructures

    International Nuclear Information System (INIS)

    Laucht, Arne

    2011-01-01

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings (ΔE ∝5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of single photon emission into the waveguide. The results obtained during the course of this thesis contribute significantly to

  14. Semiconductor quantum optics with tailored photonic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Laucht, Arne

    2011-06-15

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings ({delta}E<{proportional_to}5 meV) and a multi-exciton-based, Auger-like process for larger detunings ({delta}E >{proportional_to}5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of

  15. Synthesis, morphology, optical and photocatalytic performance of nanostructured β-Ga2O3

    International Nuclear Information System (INIS)

    Girija, K.; Thirumalairajan, S.; Avadhani, G.S.; Mangalaraj, D.; Ponpandian, N.; Viswanathan, C.

    2013-01-01

    Highlights: ► Nanostructures of β-Ga 2 O 3 were prepared using facile reflux condensation process. ► The pH of the reaction mixture shows evident influence on the size and shape of the nanostructures formed. ► The nanostructures exhibited good photocatalytic activity toward Rhodamine B and was found to be superior for higher pH value. - Abstract: Fine powders of β-Ga 2 O 3 nanostructures were prepared via low temperature reflux condensation method by varying the pH value without using any surfactant. The pH value of reaction mixture had great influence on the morphology of final products. High crystalline single phase β-Ga 2 O 3 nanostructures were obtained by thermal treatment at 900 °C which was confirmed by X-ray diffraction and Raman spectroscopy. The morphological analysis revealed rod like nanostructures at lower and higher pH values of 6 and 10, while spindle like structures were obtained at pH = 8. The phase purity and presence of vibrational bands were identified using Fourier transform infrared spectroscopy. The optical absorbance spectrum showed intense absorption features in the UV spectral region. A broad blue emission peak centered at 441 nm due to donor–acceptor gallium–oxygen vacancy pair recombination appeared. The photocatalytic activity toward Rhodamine B under visible light irradiation was higher for nanorods at pH 10

  16. Theory of hyperbolic stratified nanostructures for surface-enhanced Raman scattering

    Science.gov (United States)

    Wong, Herman M. K.; Dezfouli, Mohsen Kamandar; Axelrod, Simon; Hughes, Stephen; Helmy, Amr S.

    2017-11-01

    We theoretically investigate the enhancement of surface enhanced Raman spectroscopy (SERS) using hyperbolic stratified nanostructures and compare to metal nanoresonators. The photon Green function of each nanostructure within its environment is first obtained from a semianalytical modal theory, which is used in a quantum optics formalism of the molecule-nanostructure interaction to model the SERS spectrum. An intuitive methodology is presented for calculating the single-molecule enhancement factor (SMEF), which is also able to predict known experimental SERS enhancement factors of a gold nanodimer. We elucidate the important figures-of-merit of the enhancement and explore these for different designs. We find that the use of hyperbolic stratified materials can enhance the photonic local density of states (LDOS) by close to two times in comparison to pure metal nanostructures, when both designed to work at the same operating wavelengths. However, the increased LDOS is accompanied by higher electric field concentration within the lossy hyperbolic material, which leads to increased quenching that serves to reduce the overall detected SERS enhancement in the far field. For nanoresonators with resonant localized surface plasmon wavelengths in the near-infrared, the SMEF for the hyperbolic stratified nanostructure is approximately one order of magnitude lower than the pure metal counterpart. Conversely, we show that by detecting the Raman signal using a near-field probe, hyperbolic materials can provide an improvement in SERS enhancement compared to using pure metal nanostructures when the probe is sufficiently close (<50 nm ) to the Raman active molecule at the plasmonic hotspot.

  17. Surfactant-assisted synthesis of Ag nanostructures and their self-assembled films on copper and aluminum substrate

    International Nuclear Information System (INIS)

    Zhuo Yujiang; Sun Wendong; Dong Lihong; Chu Ying

    2011-01-01

    In this paper, silver nanostructures with controlled morphologies, such as plates, rods, belts, sheets and their self-assembled films have been prepared on copper and aluminum substrates by a surfactant-assisted colloidal chemical method. The X-ray powder diffraction (XRD) and the selected area electron diffraction (SAED) patterns indicated that the Ag nanostructures grew on the substrates with cubic symmetry and single-crystalline in nature. An oriented attachment with surfactant-assisted mechanism and a cooperative effect of surfactant and chloride ion on the morphology of Ag nanostructures were investigated systematically and synthetically.

  18. Practical roadmap and limits to nanostructured photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lunt, Richard R. [Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Osedach, Timothy P. [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Brown, Patrick R. [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Rowehl, Jill A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bulovic, Vladimir [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-12-22

    The significant research interest in the engineering of photovoltaic (PV) structures at the nanoscale is directed toward enabling reductions in PV module fabrication and installation costs as well as improving cell power conversion efficiency (PCE). With the emergence of a multitude of nanostructured photovoltaic (nano-PV) device architectures, the question has arisen of where both the practical and the fundamental limits of performance reside in these new systems. Here, the former is addressed a posteriori. The specific challenges associated with improving the electrical power conversion efficiency of various nano-PV technologies are discussed and several approaches to reduce their thermal losses beyond the single bandgap limit are reviewed. Critical considerations related to the module lifetime and cost that are unique to nano-PV architectures are also addressed. The analysis suggests that a practical single-junction laboratory power conversion efficiency limit of 17% and a two-cell tandem power conversion efficiency limit of 24% are possible for nano-PVs, which, when combined with operating lifetimes of 10 to 15 years, could position them as a transformational technology for solar energy markets. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Single Nanoparticle Plasmonic Sensors

    Directory of Open Access Journals (Sweden)

    Manish Sriram

    2015-10-01

    Full Text Available The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed.

  20. Characterization of Nanostructured Semiconductors by Ultrafast Luminescence Imaging

    Science.gov (United States)

    Blake, Jolie

    Single nanostructures are predicted to be the building blocks of next generation devices and have already been incorporated into prototypes for solar cells, biomedical devices and lasers. Their role in such applications requires a fundamental understanding of their opto-electronic properties and in particular the charge carrier dynamics occurring on an ultrafast timescale. Luminescence detection is a common approach used to investigate electronic properties of nanostructures because of the contact-less nature of these methods. They are, however, often not equipped to efficiently measure multiple single nanostructures nor do they have the temporal resolution necessary for observing femtosecond dynamics. This dissertation intends to address this paucity of techniques available for the contact-less measurement of single nanostructures through the development of an ultrafast wide-field Kerr-gated microscope system and measurement technique. The setup, operational in both the steady state and transient mode and capable of microscopic and spectroscopic measurements, was developed to measure the transient luminescence of single semiconductor nanostructures. With sub micron spatial resolution and the potential to achieve a temporal resolution greater than 90 fs, the system was used to probe the charge carrier dynamics at multiple discrete locations on single nanowires exhibiting amplified spontaneous emission. Using a rate model for amplified spontaneous emission, the transient emission data was fitted to extract the values of the competing Shockley-Read-Hall, non-geminate and Auger recombination constants. The capabilities of the setup were first demonstrated in the visible detection range, where single nanowires of the ternary alloy CdS x Se1-x were measured. The temporal emission dynamics at two separate locations were compared and calculation of the Langevin mobility revealed that the large carrier densities generated in the nanowire allows access to non

  1. Hydrothermal growth and characterizations of dandelion-like ZnO nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Rohidas B., E-mail: rb_kale@yahoo.co.in [Department of Physics, The Institute of Science, Madam Cama Road, Mumbai 400 032, (M.S.) (India); Lu, Shih-Yuan, E-mail: sylu@nthu.edu.tw [Department of Chemical Engineering, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2013-12-05

    Highlights: •The simple, low cost, environmental benign hydrothermal method has been used to synthesize ZnO nanostructure. •The SEM images reveal the interesting 3D dandelion-like morphology of synthesized ZnO nanostructure. The SAED pattern and HRTEM study confirms that the ZnO nanorods are single crystalline. •Change in experimental conditions dramatically changes the morphologies of the synthesized ZnO. •The room temperature PL study reveals strong band edge emission along with much weaker defect related blue emission. •The reaction and growth mechanism of ZnO nanostructure is also discussed. -- Abstract: Three dimensional (3D) ZnO nanostructures have been synthesized by using a facile low-cost hydrothermal method under mild conditions. Aqueous alkaline ammonia solution of Zn(CH{sub 3}COO){sub 2} is used to grow 3D ZnO nanostructures. The X-ray diffraction (XRD) study reveals the well crystallized hexagonal structure of ZnO. SEM observations depict that the ZnO product grows in the form of nanorods united together to form 3D dandelion-like nanostructures. The elemental analysis using EDAX technique confirms the stoichiometry of the ZnO nanorods. The product exhibits special optical properties with red-shifts in optical absorption peak (376 nm) as compared with those of conventional ZnO nanorods. PL spectra show emission peak (396 nm) at the near band-edge and peak (464 nm) originated from defects states that are produced during the hydrothermal growth. TEM and SAED results reveal single crystalline structure of the synthesized product. The reaction and growth mechanisms on the morphological evolution of the ZnO nanostructures are discussed. The morphology of ZnO product is investigated by varying the reaction time, temperature, and type of complexing reagent.

  2. Method to deterministically study photonic nanostructures in different experimental instruments.

    Science.gov (United States)

    Husken, B H; Woldering, L A; Blum, C; Vos, W L

    2009-01-01

    We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the nanostructure is made during the fabrication of the structure. These maps are made using a series of micrographs with successively decreasing magnifications. The graphs reveal intrinsic and characteristic geometric features that can subsequently be used in different setups to act as markers. As an illustration, we probe surface cavities with radii of 65 nm on a silica opal photonic crystal with various setups: a focused ion beam workstation; a scanning electron microscope (SEM); a wide field optical microscope and a confocal microscope. We use cross-correlation techniques to recover a small area imaged with the SEM in a large area photographed with the optical microscope, which provides a possible avenue to automatic searching. We show how both structural and optical reflectivity data can be obtained from one and the same nanostructure. Since our approach does not use artificial grids or markers, it is of particular interest for samples whose structure is not known a priori, like samples created solely by self-assembly. In addition, our method is not restricted to conducting samples.

  3. Multi-periodic nanostructures for photon control

    DEFF Research Database (Denmark)

    Kluge, Christian; Adam, Jost; Barié, Nicole

    2014-01-01

    We propose multi-periodic nanostructures yielded by superposition of multiple binary gratings for wide control over photon emission in thin-film devices. We present wavelength- and angle-resolved photoluminescence measurements of multi-periodically nanostructured organic light-emitting layers...

  4. Geometry and magnetism of L10 nanostructures

    International Nuclear Information System (INIS)

    Sorge, K.D.; Skomski, R.; Daniil, M.; Michalski, S.; Gao, L.; Zhou, J.; Yan, M.; Sui, Y.; Kirby, R.D.; Liou, S.H.; Sellmyer, D.J.

    2005-01-01

    The fabrication and magnetism of L1 0 nanostructures with different shapes (such as nanoparticles and nanotubes) is investigated. These nanostructures are produced by hydrogen processing and focused ion beam milling. The structures exhibit interesting reversal modes and are of present or potential interest for sensors and imaging, as well as magnetic recording

  5. Spin tunneling and manipulation in nanostructures.

    Science.gov (United States)

    Sherman, E Ya; Ban, Yue; Gulyaev, L V; Khomitsky, D V

    2012-09-01

    The results for joint effects of tunneling and spin-orbit coupling on spin dynamics in nanostructures are presented for systems with discrete and continuous spectra. We demonstrate that tunneling plays the crucial role in the spin dynamics and the abilities of spin manipulation by external electric field. This result can be important for design of nanostructures-based spintronics devices.

  6. Vicinal surfaces for functional nanostructures.

    Science.gov (United States)

    Tegenkamp, Christoph

    2009-01-07

    Vicinal surfaces are currently the focus of research. The regular arrangements of atomic steps on a mesoscopic scale reveal the possibility to functionalize these surfaces for technical applications, e.g. nanowires, catalysts, etc. The steps of the vicinal surface are well-defined defect structures of atomic size for nucleation of low-dimensional nanostructures. The concentration and therefore the coupling between the nanostructures can be tuned over a wide range by simply changing the inclination angle of the substrate. However, the coupling of these nano-objects to the substrate is just as important in controlling their electronic or chemical properties and making a functionality useable. On the basis of stepped insulating films, these aspects are fulfilled and will be considered in the first part of this review. Recent results for the epitaxial growth of wide bandgap insulating films (CaF(2), MgO, NaCl, BaSrO) on metallic and semiconducting vicinal substrates (Si(100), Ge(100), Ag(100)) will be presented. The change of the electronic structure, the adsorption behavior as well as the kinetics and energetics of color centers in the presence of steps is discussed. The successful bridging of the gap between the atomic and mesoscopic world, i.e. the functionalization of vicinal surfaces by nanostructures, is demonstrated in the second part by metal adsorption on semiconducting surfaces. For (sub)monolayer coverage these systems have in common that the surface states do not hybridize with the support, i.e. the semiconducting surfaces are insulating. Here I will focus on the latest results of macroscopic transport measurements on Pb quantum wires grown on vicinal Si(111) showing indeed a one-dimensional transport behavior.

  7. Vicinal surfaces for functional nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Tegenkamp, Christoph [Institut fuer Festkoerperphysik, Gottfried Wilhelm Leibniz Universitaet Hannover, Appelstrasse 2, D-30167 Hannover (Germany)], E-mail: tegenkamp@fkp.uni-hannover.de

    2009-01-07

    Vicinal surfaces are currently the focus of research. The regular arrangements of atomic steps on a mesoscopic scale reveal the possibility to functionalize these surfaces for technical applications, e.g. nanowires, catalysts, etc. The steps of the vicinal surface are well-defined defect structures of atomic size for nucleation of low-dimensional nanostructures. The concentration and therefore the coupling between the nanostructures can be tuned over a wide range by simply changing the inclination angle of the substrate. However, the coupling of these nano-objects to the substrate is just as important in controlling their electronic or chemical properties and making a functionality useable. On the basis of stepped insulating films, these aspects are fulfilled and will be considered in the first part of this review. Recent results for the epitaxial growth of wide bandgap insulating films (CaF{sub 2}, MgO, NaCl, BaSrO) on metallic and semiconducting vicinal substrates (Si(100), Ge(100), Ag(100)) will be presented. The change of the electronic structure, the adsorption behavior as well as the kinetics and energetics of color centers in the presence of steps is discussed. The successful bridging of the gap between the atomic and mesoscopic world, i.e. the functionalization of vicinal surfaces by nanostructures, is demonstrated in the second part by metal adsorption on semiconducting surfaces. For (sub)monolayer coverage these systems have in common that the surface states do not hybridize with the support, i.e. the semiconducting surfaces are insulating. Here I will focus on the latest results of macroscopic transport measurements on Pb quantum wires grown on vicinal Si(111) showing indeed a one-dimensional transport behavior. (topical review)

  8. Vicinal surfaces for functional nanostructures

    International Nuclear Information System (INIS)

    Tegenkamp, Christoph

    2009-01-01

    Vicinal surfaces are currently the focus of research. The regular arrangements of atomic steps on a mesoscopic scale reveal the possibility to functionalize these surfaces for technical applications, e.g. nanowires, catalysts, etc. The steps of the vicinal surface are well-defined defect structures of atomic size for nucleation of low-dimensional nanostructures. The concentration and therefore the coupling between the nanostructures can be tuned over a wide range by simply changing the inclination angle of the substrate. However, the coupling of these nano-objects to the substrate is just as important in controlling their electronic or chemical properties and making a functionality useable. On the basis of stepped insulating films, these aspects are fulfilled and will be considered in the first part of this review. Recent results for the epitaxial growth of wide bandgap insulating films (CaF 2 , MgO, NaCl, BaSrO) on metallic and semiconducting vicinal substrates (Si(100), Ge(100), Ag(100)) will be presented. The change of the electronic structure, the adsorption behavior as well as the kinetics and energetics of color centers in the presence of steps is discussed. The successful bridging of the gap between the atomic and mesoscopic world, i.e. the functionalization of vicinal surfaces by nanostructures, is demonstrated in the second part by metal adsorption on semiconducting surfaces. For (sub)monolayer coverage these systems have in common that the surface states do not hybridize with the support, i.e. the semiconducting surfaces are insulating. Here I will focus on the latest results of macroscopic transport measurements on Pb quantum wires grown on vicinal Si(111) showing indeed a one-dimensional transport behavior. (topical review)

  9. Solution precursor plasma deposition of nanostructured ZnO coatings

    International Nuclear Information System (INIS)

    Tummala, Raghavender; Guduru, Ramesh K.; Mohanty, Pravansu S.

    2011-01-01

    Highlights: → The solution precursor route employed is an inexpensive process with capability to produce large scale coatings at fast rates on mass scale production. → It is highly capable of developing tailorable nanostructures. → This technique can be employed to spray the coatings on any kind of substrates including polymers. → The ZnO coatings developed via solution precursor plasma spray process have good electrical conductivity and reflectivity properties in spite of possessing large amount of particulate boundaries, porosity and nanostructured grains. -- Abstract: Zinc oxide (ZnO) is a wide band gap semiconducting material that has various applications including optical, electronic, biomedical and corrosion protection. It is usually synthesized via processing routes, such as vapor deposition techniques, sol-gel, spray pyrolysis and thermal spray of pre-synthesized ZnO powders. Cheaper and faster synthesis techniques are of technological importance due to increased demand in alternative energy applications. Here, we report synthesis of nanostructured ZnO coatings directly from a solution precursor in a single step using plasma spray technique. Nanostructured ZnO coatings were deposited from the solution precursor prepared using zinc acetate and water/isopropanol. An axial liquid atomizer was employed in a DC plasma spray torch to create fine droplets of precursor for faster thermal treatment in the plasma plume to form ZnO. Microstructures of coatings revealed ultrafine particulate agglomerates. X-ray diffraction confirmed polycrystalline nature and hexagonal Wurtzite crystal structure of the coatings. Transmission electron microscopy studies showed fine grains in the range of 10-40 nm. Observed optical transmittance (∼65-80%) and reflectivity (∼65-70%) in the visible spectrum, and electrical resistivity (48.5-50.1 mΩ cm) of ZnO coatings are attributed to ultrafine particulate morphology of the coatings.

  10. Solution precursor plasma deposition of nanostructured ZnO coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tummala, Raghavender [Department of Mechanical Engineering, University of Michigan - Dearborn, MI 48128 (United States); Guduru, Ramesh K., E-mail: rkguduru@umich.edu [Department of Mechanical Engineering, University of Michigan - Dearborn, MI 48128 (United States); Mohanty, Pravansu S. [Department of Mechanical Engineering, University of Michigan - Dearborn, MI 48128 (United States)

    2011-08-15

    Highlights: {yields} The solution precursor route employed is an inexpensive process with capability to produce large scale coatings at fast rates on mass scale production. {yields} It is highly capable of developing tailorable nanostructures. {yields} This technique can be employed to spray the coatings on any kind of substrates including polymers. {yields} The ZnO coatings developed via solution precursor plasma spray process have good electrical conductivity and reflectivity properties in spite of possessing large amount of particulate boundaries, porosity and nanostructured grains. -- Abstract: Zinc oxide (ZnO) is a wide band gap semiconducting material that has various applications including optical, electronic, biomedical and corrosion protection. It is usually synthesized via processing routes, such as vapor deposition techniques, sol-gel, spray pyrolysis and thermal spray of pre-synthesized ZnO powders. Cheaper and faster synthesis techniques are of technological importance due to increased demand in alternative energy applications. Here, we report synthesis of nanostructured ZnO coatings directly from a solution precursor in a single step using plasma spray technique. Nanostructured ZnO coatings were deposited from the solution precursor prepared using zinc acetate and water/isopropanol. An axial liquid atomizer was employed in a DC plasma spray torch to create fine droplets of precursor for faster thermal treatment in the plasma plume to form ZnO. Microstructures of coatings revealed ultrafine particulate agglomerates. X-ray diffraction confirmed polycrystalline nature and hexagonal Wurtzite crystal structure of the coatings. Transmission electron microscopy studies showed fine grains in the range of 10-40 nm. Observed optical transmittance ({approx}65-80%) and reflectivity ({approx}65-70%) in the visible spectrum, and electrical resistivity (48.5-50.1 m{Omega} cm) of ZnO coatings are attributed to ultrafine particulate morphology of the coatings.

  11. Transport Properties of Nanostructured Graphene

    DEFF Research Database (Denmark)

    Jauho, Antti-Pekka

    2017-01-01

    Despite of its many wonderful properties, pristine graphene has one major drawback: it does not have a band gap, which complicates its applications in electronic devices. Many routes have been suggested to overcome this difficulty, such as cutting graphene into nanoribbons, using chemical methods...... device operation. In this talk I elaborate these ideas and review the state-of-the-art both from the theoretical and the experimental points of view. I also introduce two new ideas: (1) triangular antidots, and (2) nanobubbles formed in graphene. Both of these nanostructuring methods are predicted...

  12. Field Emission from Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Filippo Giubileo

    2018-03-01

    Full Text Available Field emission electron sources in vacuum electronics are largely considered to achieve faster response, higher efficiency and lower energy consumption in comparison with conventional thermionic emitters. Carbon nanotubes had a leading role in renewing attention to field emission technologies in the early 1990s, due to their exceptional electron emitting properties enabled by their large aspect ratio, high electrical conductivity, and thermal and chemical stability. In the last decade, the search for improved emitters has been extended to several carbon nanostructures, comprising carbon nanotubes, either individual or films, diamond structures, graphitic materials, graphene, etc. Here, we review the main results in the development of carbon-based field emitters.

  13. Nanostructured Y2O3

    International Nuclear Information System (INIS)

    Skandan, G.; Hahn, H.; Parker, J.C.

    1991-01-01

    It has been shown that a variety of nanostructured (n-) metal-oxide ceramics such as n-TiO 2 , n-ZrO 2 , n-Al 2 O 3 , n-ZnO and n-MgO can be produced using the inert gas condensation process. Amongst all the nanostructured oxides, the synthesis, microstructure, sintering, and mechanical properties of n-TiO 2 have been studied the most extensively. The gas condensation preparation of nanostructured metal-oxide ceramics involves evaporation of metal nanoparticles, collection and post- oxidation. The original synthesis studies of n-TiO 2 showed that in order to avoid formation of the many low oxidation state oxides in the Ti-O system, the post-oxidation had to be performed by rapidly exposing the Ti nanoparticles to pure oxygen gas. By doing so, the highest oxidation state and the most stable structure, rutile, was obtained. An undesired feature of this step is that the nanoparticles heat up to high temperatures for a brief period of time due to the exothermic nature of the oxidation. As a consequence, the particles with an average size of 12 nm tend to agglomerate into larger structures up to 50 nm. The agglomerated state of the powder is important since it determines the original density and pore size distribution after compaction, as well as the sintering characteristics and final microstructure of the bulk sample. As a consequence of the preparation procedure of n-TiO 2 and the resulting agglomeration, the pore size distribution of n-TiO 2 compacted at room temperature is very wide, with pore sizes ranging from 1 to 200 nm. Nevertheless, the n-TiO 2 sinters at temperatures several hundred degrees lower than conventional coarse grained ceramics. From the previous results on n- TiO 2 it is anticipated that better microstructures and properties can be achieved by reducing the agglomeration of nanostructured powders through a more controlled post- oxidation process

  14. Quantum information processing in nanostructures

    International Nuclear Information System (INIS)

    Reina Estupinan, John-Henry

    2002-01-01

    Since information has been regarded os a physical entity, the field of quantum information theory has blossomed. This brings novel applications, such as quantum computation. This field has attracted the attention of numerous researchers with backgrounds ranging from computer science, mathematics and engineering, to the physical sciences. Thus, we now have an interdisciplinary field where great efforts are being made in order to build devices that should allow for the processing of information at a quantum level, and also in the understanding of the complex structure of some physical processes at a more basic level. This thesis is devoted to the theoretical study of structures at the nanometer-scale, 'nanostructures', through physical processes that mainly involve the solid-state and quantum optics, in order to propose reliable schemes for the processing of quantum information. Initially, the main results of quantum information theory and quantum computation are briefly reviewed. Next, the state-of-the-art of quantum dots technology is described. In so doing, the theoretical background and the practicalities required for this thesis are introduced. A discussion of the current quantum hardware used for quantum information processing is given. In particular, the solid-state proposals to date are emphasised. A detailed prescription is given, using an optically-driven coupled quantum dot system, to reliably prepare and manipulate exciton maximally entangled Bell and Greenberger-Horne-Zeilinger (GHZ) states. Manipulation of the strength and duration of selective light-pulses needed for producing these highly entangled states provides us with crucial elements for the processing of solid-state based quantum information. The all-optical generation of states of the so-called Bell basis for a system of two quantum dots (QDs) is exploited for performing the quantum teleportation of the excitonic state of a dot in an array of three coupled QDs. Theoretical predictions suggest

  15. Hot-Spot Engineering in 3D Multi-Branched Nanostructures

    DEFF Research Database (Denmark)

    Chirumamilla, Manohar; Chirumamilla, Anisha; Roberts, Alexander

    2017-01-01

    The detection of probe molecules at ultralow concentrations, even at the single-molecule level, can be addressed with the breakthrough concept of plasmonic hot-spot engineering. In view of that, the fabrication of nanostructures endowed with sub-10 nm gaps and extremely large near-field enhanceme...

  16. Synthesis of carbon nanostructures from high density polyethylene (HDPE) and polyethylene terephthalate (PET) waste by chemical vapour deposition

    Science.gov (United States)

    Hatta, M. N. M.; Hashim, M. S.; Hussin, R.; Aida, S.; Kamdi, Z.; Ainuddin, AR; Yunos, MZ

    2017-10-01

    In this study, carbon nanostructures were synthesized from High Density Polyethylene (HDPE) and Polyethylene terephthalate (PET) waste by single-stage chemical vapour deposition (CVD) method. In CVD, iron was used as catalyst and pyrolitic of carbon source was conducted at temperature 700, 800 and 900°C for 30 minutes. Argon gas was used as carrier gas with flow at 90 sccm. The synthesized carbon nanostructures were characterized by FESEM, EDS and calculation of carbon yield (%). FESEM micrograph shows that the carbon nanostructures were only grown as nanofilament when synthesized from PET waste. The synthesization of carbon nanostructure at 700°C was produced smooth and the smallest diameter nanofilament compared to others. The carbon yield of synthesized carbon nanostructures from PET was lower from HDPE. Furthermore, the carbon yield is recorded to increase with increasing of reaction temperature for all samples. Elemental study by EDS analysis were carried out and the formation of carbon nanostructures was confirmed after CVD process. Utilization of polymer waste to produce carbon nanostructures is beneficial to ensure that the carbon nanotechnology will be sustained in future.

  17. Elucidation of the electrochromic mechanism of nanostructured iron oxides films

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lobato, M.A.; Martinez, Arturo I.; Castro-Roman, M. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav Campus Saltillo, Carr. Saltillo-Monterrey Km. 13, Ramos Arizpe, Coah. 25900 (Mexico); Perry, Dale L. [Mail Stop 70A1150, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Zarate, R.A. [Departamento de Fisica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Escobar-Alarcon, L. (Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico)

    2011-02-15

    Nanostructured hematite thin films were electrochemically cycled in an aqueous solution of LiOH. Through optical, structural, morphological, and magnetic measurements, the coloration mechanism of electrochromic iron oxide thin films was elucidated. The conditions for double or single electrochromic behavior are given in this work. During the electrochemical cycling, it was found that topotactic transformations of hexagonal crystal structures are favored; i.e. {alpha}-Fe{sub 2}O{sub 3} to Fe(OH){sub 2} and subsequently to {delta}-FeOOH. These topotactic redox reactions are responsible for color changes of iron oxide films. (author)

  18. Inorganic nanostructure-organic polymer heterostructures useful for thermoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    See, Kevin C.; Urban, Jeffrey J.; Segalman, Rachel A.; Coates, Nelson E.; Yee, Shannon K.

    2017-11-28

    The present invention provides for an inorganic nanostructure-organic polymer heterostructure, useful as a thermoelectric composite material, comprising (a) an inorganic nanostructure, and (b) an electrically conductive organic polymer disposed on the inorganic nanostructure. Both the inorganic nanostructure and the electrically conductive organic polymer are solution-processable.

  19. Process Development for Nanostructured Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.

    2015-01-01

    Photovoltaic manufacturing is an emerging industry that promises a carbon-free, nearly limitless source of energy for our nation. However, the high-temperature manufacturing processes used for conventional silicon-based photovoltaics are extremely energy-intensive and expensive. This high cost imposes a critical barrier to the widespread implementation of photovoltaic technology. Argonne National Laboratory and its partners recently invented new methods for manufacturing nanostructured photovoltaic devices that allow dramatic savings in materials, process energy, and cost. These methods are based on atomic layer deposition, a thin film synthesis technique that has been commercialized for the mass production of semiconductor microelectronics. The goal of this project was to develop these low-cost fabrication methods for the high efficiency production of nanostructured photovoltaics, and to demonstrate these methods in solar cell manufacturing. We achieved this goal in two ways: 1) we demonstrated the benefits of these coatings in the laboratory by scaling-up the fabrication of low-cost dye sensitized solar cells; 2) we used our coating technology to reduce the manufacturing cost of solar cells under development by our industrial partners.

  20. Space charge in nanostructure resonances

    Science.gov (United States)

    Price, Peter J.

    1996-10-01

    In quantum ballistic propagation of electrons through a variety of nanostructures, resonance in the energy-dependent transmission and reflection probabilities generically is associated with (1) a quasi-level with a decay lifetime, and (2) a bulge in electron density within the structure. It can be shown that, to a good approximation, a simple formula in all cases connects the density of states for the latter to the energy dependence of the phase angles of the eigen values of the S-matrix governing the propagation. For both the Lorentzian resonances (normal or inverted) and for the Fano-type resonances, as a consequence of this eigen value formula, the space charge due to filled states over the energy range of a resonance is just equal (for each spin state) to one electron charge. The Coulomb interaction within this space charge is known to 'distort' the electrical characteristics of resonant nanostructures. In these systems, however, the exchange effect should effectively cancel the interaction between states with parallel spins, leaving only the anti-parallel spin contribution.

  1. Quantitative Characterization of Nanostructured Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Frank (Bud) Bridges, University of California-Santa Cruz

    2010-08-05

    The two-and-a-half day symposium on the "Quantitative Characterization of Nanostructured Materials" will be the first comprehensive meeting on this topic held under the auspices of a major U.S. professional society. Spring MRS Meetings provide a natural venue for this symposium as they attract a broad audience of researchers that represents a cross-section of the state-of-the-art regarding synthesis, structure-property relations, and applications of nanostructured materials. Close interactions among the experts in local structure measurements and materials researchers will help both to identify measurement needs pertinent to real-world materials problems and to familiarize the materials research community with the state-of-the-art local structure measurement techniques. We have chosen invited speakers that reflect the multidisciplinary and international nature of this topic and the need to continually nurture productive interfaces among university, government and industrial laboratories. The intent of the symposium is to provide an interdisciplinary forum for discussion and exchange of ideas on the recent progress in quantitative characterization of structural order in nanomaterials using different experimental techniques and theory. The symposium is expected to facilitate discussions on optimal approaches for determining atomic structure at the nanoscale using combined inputs from multiple measurement techniques.

  2. Self-assembly of subwavelength nanostructures with symmetry breaking in solution

    Science.gov (United States)

    Tian, Xiang-Dong; Chen, Shu; Zhang, Yue-Jiao; Dong, Jin-Chao; Panneerselvam, Rajapandiyan; Zhang, Yun; Yang, Zhi-Lin; Li, Jian-Feng; Tian, Zhong-Qun

    2016-01-01

    Nanostructures with symmetry breaking can allow the coupling between dark and bright plasmon modes to induce strong Fano resonance. However, it is still a daunting challenge to prepare bottom-up self-assembled subwavelength asymmetric nanostructures with appropriate gaps between the nanostructures especially below 5 nm in solution. Here we present a viable self-assembly method to prepare symmetry-breaking nanostructures consisting of Ag nanocubes and Au nanospheres both with tunable size (90-250 nm for Au nanospheres; 100-160 nm for Ag nanocubes) and meanwhile control the nanogaps through ultrathin silica shells of 1-5 nm thickness. The Raman tag of 4-mercaptobenzoic acid (MBA) assists the self-assembly process and endows the subwavelength asymmetric nanostructures with surface-enhanced Raman scattering (SERS) activity. Moreover, thick silica shells (above 50 nm thickness) can be coated on the self-assembled nanostructures in situ to stabilize the whole nanostructures, paving the way toward bioapplications. Single particle scattering spectroscopy with a 360° polarization resolution is performed on individual Ag nanocube and Au nanosphere dimers, correlated with high-resolution TEM characterization. The asymmetric dimers exhibit strong configuration and polarization dependence Fano resonance properties. Overall, the solution-based self-assembly method reported here is opening up new opportunities to prepare diverse multicomponent nanomaterials with optimal performance.Nanostructures with symmetry breaking can allow the coupling between dark and bright plasmon modes to induce strong Fano resonance. However, it is still a daunting challenge to prepare bottom-up self-assembled subwavelength asymmetric nanostructures with appropriate gaps between the nanostructures especially below 5 nm in solution. Here we present a viable self-assembly method to prepare symmetry-breaking nanostructures consisting of Ag nanocubes and Au nanospheres both with tunable size (90-250 nm

  3. Lifetime of Nano-Structured Black Silicon for Photovoltaic Applications

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym; Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

    2016-01-01

    In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping pro......, respectively. This is promising for use of black silicon RIE nano-structuring in a solar cell process flow......In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping...

  4. Polar order in nanostructured organic materials

    Science.gov (United States)

    Sayar, M.; Olvera de la Cruz, M.; Stupp, S. I.

    2003-02-01

    Achiral multi-block liquid crystals are not expected to form polar domains. Recently, however, films of nanoaggregates formed by multi-block rodcoil molecules were identified as the first example of achiral single-component materials with macroscopic polar properties. By solving an Ising-like model with dipolar and asymmetric short-range interactions, we show here that polar domains are stable in films composed of aggregates as opposed to isolated molecules. Unlike classical molecular systems, these nanoaggregates have large intralayer spacings (a approx 8 nm), leading to a reduction in the repulsive dipolar interactions which oppose polar order within layers. In finite-thickness films of nanostructures, this effect enables the formation of polar domains. We compute exactly the energies of the possible structures consistent with the experiments as a function of film thickness at zero temperature (T). We also provide Monte Carlo simulations at non-zero T for a disordered hexagonal lattice that resembles the smectic-like packing in these nanofilms.

  5. Hydrogen adsorption in carbon nanostructures compared

    International Nuclear Information System (INIS)

    Schimmel, H.G.; Nijkamp, G.; Kearley, G.J.; Rivera, A.; Jong, K.P. de; Mulder, F.M.

    2004-01-01

    Recent reports continue to suggest high hydrogen storage capacities for some carbon nanostructures due to a stronger interaction between hydrogen and carbon. Here the interaction of hydrogen with activated charcoal, carbon nanofibers, single walled carbon nanotubes (SWNT), and electron beam 'opened' SWNT are compared and shown to be similar. The storage capacity below 77 K of these materials correlates with the surface area of the material with the activated charcoal having the largest. SWNT and 'opened' SWNT have a relatively low accessible surface area due to bundling of the tubes. Pressure-temperature curves give the interaction potential, which was found to be ∼580 K or 50 meV in all samples, leading to significant adsorption below ∼50 K. Using the inelastic neutron scattering signal associated with rotation of the hydrogen molecule as a sensitive probe for the surroundings of the molecule, no difference was found between the hydrogen molecules adsorbed in the investigated materials. These combined spectroscopic and macroscopic results show that SWNT, nanofibers and activated carbons store molecular hydrogen due to their graphitic nature and not because they possess special morphologies. Results from a density functional theory computer calculation suggest molecular hydrogen bonding to an aromatic C-C bond of graphite, irrespective of the surface morphology farther away

  6. Zinc oxide nanostructures for electrochemical cortisol biosensing

    Science.gov (United States)

    Vabbina, Phani Kiran; Kaushik, Ajeet; Tracy, Kathryn; Bhansali, Shekhar; Pala, Nezih

    2014-05-01

    In this paper, we report on fabrication of a label free, highly sensitive and selective electrochemical cortisol immunosensors using one dimensional (1D) ZnO nanorods (ZnO-NRs) and two dimensional nanoflakes (ZnO-NFs) as immobilizing matrix. The synthesized ZnO nanostructures (NSs) were characterized using scanning electron microscopy (SEM), selective area diffraction (SAED) and photoluminescence spectra (PL) which showed that both ZnO-NRs and ZnO-NFs are single crystalline and oriented in [0001] direction. Anti-cortisol antibody (Anti-Cab) are used as primary capture antibodies to detect cortisol using electrochemical impedance spectroscopy (EIS). The charge transfer resistance increases linearly with increase in cortisol concentration and exhibits a sensitivity of 3.078 KΩ. M-1 for ZnO-NRs and 540 Ω. M -1 for ZnO-NFs. The developed ZnO-NSs based immunosensor is capable of detecting cortisol at 1 pM. The observed sensing parameters are in physiological range. The developed sensors can be integrated with microfluidic system and miniaturized potentiostat to detect cortisol at point-of-care.

  7. Angle resolved characterization of nanostructured and conventionally textured silicon solar cells

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Ormstrup, Jeppe; Ommen, Martin Lind

    2015-01-01

    current, open circuit voltage, fill factor (FF) and power conversion efficiency are each measured as function of the relative incident angle between the solar cell and the light source. The relative incident angle is varied from 0° to 90° in steps of 10° in orthogonal axes, such that each solar cell......We report angle resolved characterization of nanostructured and conventionally textured silicon solar cells. The nanostructured solar cells are realized through a single step, mask-less, scalable reactive ion etching (RIE) texturing of the surface. Photovoltaic properties including short circuit...

  8. Enhanced absorption of graphene in the visible region by use of plasmonic nanostructures

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Farzad, Mahmood Hosseini; Mortensen, N. Asger

    2013-01-01

    Low absorption of graphene in the visible range of the spectrum makes it difficult to uniquely benefit from this material in ultra-fast optoelectronic applications. We numerically propose to utilize patterned metallic nanostructures to increase light absorption in single-layer graphene. Simulation...... results show that excitation of surface plasmon resonances in the metallic nanostructures significantly enhances the local electromagnetic field near the graphene layer, therefore leading to a dramatic enhancement of the absorption in the graphene layer itself. Broadband high optical absorption can...

  9. Silicon-embedded copper nanostructure network for high energy storage

    Science.gov (United States)

    Yu, Tianyue

    2016-03-15

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  10. Silicon-embedded copper nanostructure network for high energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Tianyue

    2018-01-23

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  11. SrZnO nanostructures grown on templated Al2O3 substrates by pulsed laser deposition

    Science.gov (United States)

    Labis, Joselito P.; Alanazi, Anwar Q.; Albrithen, Hamad A.; El-Toni, Ahmed Mohamed; Hezam, Mahmoud; Elafifi, Hussein Elsayed; Abaza, Osama M.

    2017-09-01

    The parameters of pulsed laser deposition (PLD) have been optimized to design different nanostructures of Strontium-alloyed zinc oxide (SrZnO). In this work, SrZnO nanostructures are grown on Al2O3 substrates via two-step templating/seeding approach. In the temperature range between 300 - 750 oC and O2 background pressures between 0.01 and 10 Torr, the growth conditions have been tailored to grow unique pointed leaf-like- and pitted olive-like nanostructures. Prior to the growth of the nanostructures, a thin SrZnO layer that serves as seed layer/template is first deposited on the Al2O3 substrates at ˜300oC and background oxygen pressure of 10 mTorr. The optical properties of the nanostructures were examined by UV/Vis spectroscopy and photoluminescence (PL), while the structures/morphologies were examined by SEM, TEM, and XRD. The alloyed SrZnO nanostructures, grown by ablating ZnO targets with 5, 10, 25% SrO contents, have in common a single-crystal hexagonal nanostructure with (0002) preferential orientation and have shown remarkable changes in the morphological and optical properties of the materials. To date, this is the only reported work on optimization of laser ablation parameters to design novel SrZnO nanostructures in the 5-25% alloying range, as most related Sr-doped ZnO studies were done below 7% doping. Although the physical properties of ZnO are modified via Sr doping, the mechanism remains unclear. The PLD-grown SrZnO nanostructures were directly grown onto the Al2O3 substrates; thus making these nanomaterials very promising for potential applications in biosensors, love-wave filters, solar cells, and ultrasonic oscillators.

  12. SrZnO nanostructures grown on templated Al2O3 substrates by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    Joselito P. Labis

    2017-09-01

    Full Text Available The parameters of pulsed laser deposition (PLD have been optimized to design different nanostructures of Strontium-alloyed zinc oxide (SrZnO. In this work, SrZnO nanostructures are grown on Al2O3 substrates via two-step templating/seeding approach. In the temperature range between 300 - 750 oC and O2 background pressures between 0.01 and 10 Torr, the growth conditions have been tailored to grow unique pointed leaf-like- and pitted olive-like nanostructures. Prior to the growth of the nanostructures, a thin SrZnO layer that serves as seed layer/template is first deposited on the Al2O3 substrates at ∼300oC and background oxygen pressure of 10 mTorr. The optical properties of the nanostructures were examined by UV/Vis spectroscopy and photoluminescence (PL, while the structures/morphologies were examined by SEM, TEM, and XRD. The alloyed SrZnO nanostructures, grown by ablating ZnO targets with 5, 10, 25% SrO contents, have in common a single-crystal hexagonal nanostructure with (0002 preferential orientation and have shown remarkable changes in the morphological and optical properties of the materials. To date, this is the only reported work on optimization of laser ablation parameters to design novel SrZnO nanostructures in the 5-25% alloying range, as most related Sr-doped ZnO studies were done below 7% doping. Although the physical properties of ZnO are modified via Sr doping, the mechanism remains unclear. The PLD-grown SrZnO nanostructures were directly grown onto the Al2O3 substrates; thus making these nanomaterials very promising for potential applications in biosensors, love-wave filters, solar cells, and ultrasonic oscillators.

  13. Nanostructured transparent conducting oxide electrochromic device

    Science.gov (United States)

    Milliron, Delia; Tangirala, Ravisubhash; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2016-05-17

    The embodiments described herein provide an electrochromic device. In an exemplary embodiment, the electrochromic device includes (1) a substrate and (2) a film supported by the substrate, where the film includes transparent conducting oxide (TCO) nanostructures. In a further embodiment, the electrochromic device further includes (a) an electrolyte, where the nanostructures are embedded in the electrolyte, resulting in an electrolyte, nanostructure mixture positioned above the substrate and (b) a counter electrode positioned above the mixture. In a further embodiment, the electrochromic device further includes a conductive coating deposited on the substrate between the substrate and the mixture. In a further embodiment, the electrochromic device further includes a second substrate positioned above the mixture.

  14. Nanostructured thin films and coatings functional properties

    CERN Document Server

    Zhang, Sam

    2010-01-01

    The second volume in ""The Handbook of Nanostructured Thin Films and Coatings"" set, this book focuses on functional properties, including optical, electronic, and electrical properties, as well as related devices and applications. It explores the large-scale fabrication of functional thin films with nanoarchitecture via chemical routes, the fabrication and characterization of SiC nanostructured/nanocomposite films, and low-dimensional nanocomposite fabrication and applications. The book also presents the properties of sol-gel-derived nanostructured thin films as well as silicon nanocrystals e

  15. Ceramic nanostructures and methods of fabrication

    Science.gov (United States)

    Ripley, Edward B [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Morrell, Jonathan S [Knoxville, TN

    2009-11-24

    Structures and methods for the fabrication of ceramic nanostructures. Structures include metal particles, preferably comprising copper, disposed on a ceramic substrate. The structures are heated, preferably in the presence of microwaves, to a temperature that softens the metal particles and preferably forms a pool of molten ceramic under the softened metal particle. A nano-generator is created wherein ceramic material diffuses through the molten particle and forms ceramic nanostructures on a polar site of the metal particle. The nanostructures may comprise silica, alumina, titania, or compounds or mixtures thereof.

  16. Understanding the ordering mechanisms of self-assembled nanostructures of block copolymers during zone annealing

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Zhinan; Zhang, Liangshun, E-mail: zhangls@ecust.edu.cn, E-mail: jlin@ecust.edu.cn; Wang, Liquan; Lin, Jiaping, E-mail: zhangls@ecust.edu.cn, E-mail: jlin@ecust.edu.cn [Shanghai Key Laboratory of Advanced Polymeric Materials, State Key Laboratory of Bioreactor Engineering, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-03-21

    A theoretical method based on dynamic version of self-consistent field theory is extended to investigate directed self-assembly behaviors of block copolymers subjected to zone annealing. The ordering mechanisms and orientation modulation of microphase-separated nanostructures of block copolymers are discussed in terms of sweep velocity, wall preference, and Flory-Huggins interaction parameter. The simulated results demonstrate that the long-range ordered nanopatterns are achieved by lowering the sweep velocity of zone annealing due to the incorporation of templated ordering of block copolymers. The surface enrichment by one of the two polymer species induces the orientation modulation of defect-free nanostructures through finely tuning the composition of block copolymers and the preference of walls. Additionally, the Flory-Huggins interaction parameters of block copolymers in the distinct regions are main factors to design the zone annealing process for creating the highly ordered nanostructures with single orientation.

  17. Natural nanostructure and superlattice nanodomains in AgSbTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, Christopher E.; De Armas, Ricardo; Shao-Horn, Yang, E-mail: delaireoa@ornl.gov, E-mail: shaohorn@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ma, Jie [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); May, Andrew F.; Delaire, Olivier, E-mail: delaireoa@ornl.gov, E-mail: shaohorn@mit.edu [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-04-14

    AgSbTe{sub 2} has long been of interest for thermoelectric applications because of its favorable electronic properties and its low lattice thermal conductivity of ∼0.7 W/mK. In this work, we report new findings from a high-resolution transmission electron microscopy study revealing two nanostructures in single crystal Ag{sub 1−x}Sb{sub 1+x}Sb{sub 2+x} (with x = 0, 0.1, 0.2); (i) a rippled natural nanostructure with a period of ∼2.5–5 nm and (ii) superlattice ordered nanodomains consistent with cation ordering predicted in previous density functional theory studies. These nanostructures, combined with point-defects, probably serve as sources of scattering for phonons, thereby yielding a low lattice thermal conductivity over a wide temperature range.

  18. Multi-particle assembled porous nanostructured MgO: its application in fluoride removal

    International Nuclear Information System (INIS)

    Gangaiah, Vijayakumar; Chandrappa, Gujjarahalli Thimanna; Siddaramanna, Ashoka

    2014-01-01

    In this article, a simple and economical route based on ethylene glycol mediated process was developed to synthesize one-dimensional (1D) multiparticle assembled nanostructured MgO using magnesium acetate and urea as reactants. Porous multiparticle chain-like MgO has been synthesized by the calcination of a solvothermally derived single nanostructured precursor. The prepared products were characterized by an x-ray diffraction (XRD) pattern, thermogravimetry, scanning/transmission electron microscopy (SEM/TEM) and N 2 adsorption (BET). As a proof of concept, the porous multiparticle chain-like MgO has been applied in a water treatment for isolated and rural communities, and it has exhibited an excellent adsorption capability to remove fluoride in waste water. In addition, this method could be generalized to prepare other 1D nanostructures with great potential for various attractive applications. (paper)

  19. Invited Article: Autonomous assembly of atomically perfect nanostructures using a scanning tunneling microscope.

    Science.gov (United States)

    Celotta, Robert J; Balakirsky, Stephen B; Fein, Aaron P; Hess, Frank M; Rutter, Gregory M; Stroscio, Joseph A

    2014-12-01

    A major goal of nanotechnology is to develop the capability to arrange matter at will by placing individual atoms at desired locations in a predetermined configuration to build a nanostructure with specific properties or function. The scanning tunneling microscope has demonstrated the ability to arrange the basic building blocks of matter, single atoms, in two-dimensional configurations. An array of various nanostructures has been assembled, which display the quantum mechanics of quantum confined geometries. The level of human interaction needed to physically locate the atom and bring it to the desired location limits this atom assembly technology. Here we report the use of autonomous atom assembly via path planning technology; this allows atomically perfect nanostructures to be assembled without the need for human intervention, resulting in precise constructions in shorter times. We demonstrate autonomous assembly by assembling various quantum confinement geometries using atoms and molecules and describe the benefits of this approach.

  20. Invited Article: Autonomous assembly of atomically perfect nanostructures using a scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Celotta, Robert J., E-mail: robert.celotta@nist.gov, E-mail: joseph.stroscio@nist.gov; Hess, Frank M.; Rutter, Gregory M.; Stroscio, Joseph A., E-mail: robert.celotta@nist.gov, E-mail: joseph.stroscio@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Balakirsky, Stephen B. [Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Georgia Tech Research Institute, Atlanta, Georgia 30332 (United States); Fein, Aaron P. [Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2014-12-15

    A major goal of nanotechnology is to develop the capability to arrange matter at will by placing individual atoms at desired locations in a predetermined configuration to build a nanostructure with specific properties or function. The scanning tunneling microscope has demonstrated the ability to arrange the basic building blocks of matter, single atoms, in two-dimensional configurations. An array of various nanostructures has been assembled, which display the quantum mechanics of quantum confined geometries. The level of human interaction needed to physically locate the atom and bring it to the desired location limits this atom assembly technology. Here we report the use of autonomous atom assembly via path planning technology; this allows atomically perfect nanostructures to be assembled without the need for human intervention, resulting in precise constructions in shorter times. We demonstrate autonomous assembly by assembling various quantum confinement geometries using atoms and molecules and describe the benefits of this approach.

  1. Invited Article: Autonomous assembly of atomically perfect nanostructures using a scanning tunneling microscope

    International Nuclear Information System (INIS)

    Celotta, Robert J.; Hess, Frank M.; Rutter, Gregory M.; Stroscio, Joseph A.; Balakirsky, Stephen B.; Fein, Aaron P.

    2014-01-01

    A major goal of nanotechnology is to develop the capability to arrange matter at will by placing individual atoms at desired locations in a predetermined configuration to build a nanostructure with specific properties or function. The scanning tunneling microscope has demonstrated the ability to arrange the basic building blocks of matter, single atoms, in two-dimensional configurations. An array of various nanostructures has been assembled, which display the quantum mechanics of quantum confined geometries. The level of human interaction needed to physically locate the atom and bring it to the desired location limits this atom assembly technology. Here we report the use of autonomous atom assembly via path planning technology; this allows atomically perfect nanostructures to be assembled without the need for human intervention, resulting in precise constructions in shorter times. We demonstrate autonomous assembly by assembling various quantum confinement geometries using atoms and molecules and describe the benefits of this approach

  2. RHEED transmission mode and pole figures thin film and nanostructure texture analysis

    CERN Document Server

    Wang, Gwo-Ching

    2014-01-01

    This unique book covers the fundamental principle of electron diffraction, basic instrumentation of RHEED, definitions of textures in thin films and nanostructures, mechanisms and control of texture formation, and examples of RHEED transmission mode measurements of texture and texture evolution of thin films and nanostructures. Also presented is a new application of RHEED in the transmission mode called RHEED pole figure technique that can be used to monitor the texture evolution in thin film growth and nanostructures and is not limited to single crystal epitaxial film growth. Details of the construction of RHEED pole figures and the interpretation of observed pole figures are presented.  Materials covered include metals, semiconductors, and thin insulators. This book also: Presents a new application of RHEED in the transmission mode Introduces a variety of textures from metals, semiconductors, compound semiconductors, and their characteristics in RHEED pole figures Provides examples of RHEED measurements o...

  3. Hybrid luminescent/magnetic nanostructured porous silicon particles for biomedical applications

    Science.gov (United States)

    Muñoz-Noval, Álvaro; Sánchez-Vaquero, Vanessa; Torres-Costa, Vicente; Gallach, Darío; Ferro-Llanos, Vicente; Javier Serrano, José; Manso-Silván, Miguel; García-Ruiz, Josefa Predestinación; Del Pozo, Francisco; Martín-Palma, Raúl J.

    2011-02-01

    This work describes a novel process for the fabrication of hybrid nanostructured particles showing intense tunable photoluminescence and a simultaneous ferromagnetic behavior. The fabrication process involves the synthesis of nanostructured porous silicon (NPSi) by chemical anodization of crystalline silicon and subsequent in pore growth of Co nanoparticles by electrochemically-assisted infiltration. Final particles are obtained by subsequent sonication of the Co-infiltrated NPSi layers and conjugation with poly(ethylene glycol) aiming at enhancing their hydrophilic character. These particles respond to magnetic fields, emit light in the visible when excited in the UV range, and internalize into human mesenchymal stem cells with no apoptosis induction. Furthermore, cytotoxicity in in-vitro systems confirms their biocompatibility and the viability of the cells after incorporation of the particles. The hybrid nanostructured particles might represent powerful research tools as cellular trackers or in cellular therapy since they allow combining two or more properties into a single particle.

  4. Magnetic resonance of semiconductors and their nanostructures basic and advanced applications

    CERN Document Server

    Baranov, Pavel G; Jelezko, Fedor; Wrachtrup, Jörg

    2017-01-01

    This book explains different magnetic resonance (MR) techniques and uses different combinations of these techniques to analyze defects in semiconductors and nanostructures. It also introduces novelties such as single defects MR and electron-paramagnetic-resonance-based methods: electron spin echo, electrically detected magnetic resonance, optically detected magnetic resonance and electron-nuclear double resonance – the designated tools for investigating the structural and spin properties of condensed systems, living matter, nanostructures and nanobiotechnology objects. Further, the authors address problems existing in semiconductor and nanotechnology sciences that can be resolved using MR, and discuss past, current and future applications of MR, with a focus on advances in MR methods. The book is intended for researchers in MR studies of semiconductors and nanostructures wanting a comprehensive review of what has been done in their own and related fields of study, as well as future perspectives.

  5. Using reflectance anisotropy spectroscopy to characterize capped silver nanostructures grown on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fleischer, K.; Jacob, J.; McGilp, J.F. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Chandola, S. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); ISAS - Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Strasse 9, 12489 Berlin (Germany); Esser, N. [ISAS - Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

    2008-07-01

    Using the single domain Si(111)-3 x 1-Ag surface as a template, room temperature deposition of two or more monolayers of Ag leads to the formation of metallic nanostructures. Reflectance anisotropy spectroscopy (RAS) in the infrared (IR) spectral region is used to analyse the anisotropic conductivity of the structures. The anisotropy is found to be influenced by the offcut angle of the substrate, and hence the terrace width. The Ag nanostructures were capped with Si to form a near-IR transparent protecting layer. The samples are stable to exposure to ambient conditions for significant periods. The RAS spectra are compared to model calculations, which support the conclusion that the buried metallic Ag nanostructures survive the capping process. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Effects of Irregular Bimetallic Nanostructures on the Optical Properties of Photosystem I from Thermosynechococcus elongatus

    Directory of Open Access Journals (Sweden)

    Imran Ashraf

    2015-07-01

    Full Text Available The fluorescence of photosystem I (PSI trimers in proximity to bimetallic plasmonic nanostructures have been explored by single-molecule spectroscopy (SMS at cryogenic temperature (1.6 K. PSI serves as a model for biological multichromophore-coupled systems with high potential for biotechnological applications. Plasmonic nanostructures are fabricated by thermal annealing of thin metallic films. The fluorescence of PSI has been intensified due to the coupling with plasmonic nanostructures. Enhancement factors up to 22.9 and 5.1 are observed for individual PSI complexes coupled to Au/Au and Ag/Au samples, respectively. Additionally, a wavelength dependence of fluorescence enhancement is observed, which can be explained by the multichromophoric composition of PSI.

  7. nanostructures

    Indian Academy of Sciences (India)

    Wintec

    In this method no special electrolytes, chemicals and surfactants are needed. ... tures collected from the bottom of the cell are either nanothreads embodying beads of different diameters,. ~10–40 nm or .... when copious oxygen produced through electrolysis at- ... corresponding bandgap calculations of the as synthesized.

  8. Silver nanostructures with well-controlled shapes: synthesis, characterization and growth mechanisms

    International Nuclear Information System (INIS)

    Kan Caixia; Zhu Jiejun; Zhu Xiaoguang

    2008-01-01

    This paper describes a poly(vinylpyrollidone)-directed polyol synthesis method for the fabrication of silver (Ag) nanostructures with well-controlled shapes (such as nanorods and nanocubes) by adjusting the synthesizing parameters. The structure characterizations suggest that the Ag nanorods grow from the five-fold twinned decahedral crystal nuclei. The nature of the {1 1 1} planes of Ag crystal and the highly selective poly(vinylpyrollidone) adsorption on the {100} planes of Ag crystal nuclei are favourable for the formation of Ag nanorods and Ag nanowires. The single crystalline Ag nanocubes obtained at optimum conditions are perfect in shape and are enclosed by the {1 0 0} facets. The optical properties of the Ag nanostructures show an attractive plasma resonance, displaying a considerable dependence on the shape and size. The formation of the Ag nanostructures with well-defined shapes is probably due to the fact that the nanostructures are controlled thermodynamically and kinetically. The ability to generate shape-controlled Ag nanostructures also provides an opportunity to experimentally and systematically study the relationship between their properties and geometric shapes

  9. Three-Dimensional ZnO Hierarchical Nanostructures: Solution Phase Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Xiaoliang Wang

    2017-11-01

    Full Text Available Zinc oxide (ZnO nanostructures have been studied extensively in the past 20 years due to their novel electronic, photonic, mechanical and electrochemical properties. Recently, more attention has been paid to assemble nanoscale building blocks into three-dimensional (3D complex hierarchical structures, which not only inherit the excellent properties of the single building blocks but also provide potential applications in the bottom-up fabrication of functional devices. This review article focuses on 3D ZnO hierarchical nanostructures, and summarizes major advances in the solution phase synthesis, applications in environment, and electrical/electrochemical devices. We present the principles and growth mechanisms of ZnO nanostructures via different solution methods, with an emphasis on rational control of the morphology and assembly. We then discuss the applications of 3D ZnO hierarchical nanostructures in photocatalysis, field emission, electrochemical sensor, and lithium ion batteries. Throughout the discussion, the relationship between the device performance and the microstructures of 3D ZnO hierarchical nanostructures will be highlighted. This review concludes with a personal perspective on the current challenges and future research.

  10. Silver nanostructures with well-controlled shapes: synthesis, characterization and growth mechanisms

    Science.gov (United States)

    Kan, Cai-Xia; Zhu, Jie-Jun; Zhu, Xiao-Guang

    2008-08-01

    This paper describes a poly(vinylpyrollidone)-directed polyol synthesis method for the fabrication of silver (Ag) nanostructures with well-controlled shapes (such as nanorods and nanocubes) by adjusting the synthesizing parameters. The structure characterizations suggest that the Ag nanorods grow from the five-fold twinned decahedral crystal nuclei. The nature of the {1 1 1} planes of Ag crystal and the highly selective poly(vinylpyrollidone) adsorption on the {100} planes of Ag crystal nuclei are favourable for the formation of Ag nanorods and Ag nanowires. The single crystalline Ag nanocubes obtained at optimum conditions are perfect in shape and are enclosed by the {1 0 0} facets. The optical properties of the Ag nanostructures show an attractive plasma resonance, displaying a considerable dependence on the shape and size. The formation of the Ag nanostructures with well-defined shapes is probably due to the fact that the nanostructures are controlled thermodynamically and kinetically. The ability to generate shape-controlled Ag nanostructures also provides an opportunity to experimentally and systematically study the relationship between their properties and geometric shapes.

  11. Silver nanostructures with well-controlled shapes: synthesis, characterization and growth mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Kan Caixia [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China); Zhu Jiejun [Department of Physics, Nanjing University, Nanjing 210093 (China); Zhu Xiaoguang [Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: cxkan@nuaa.edu.cn

    2008-08-07

    This paper describes a poly(vinylpyrollidone)-directed polyol synthesis method for the fabrication of silver (Ag) nanostructures with well-controlled shapes (such as nanorods and nanocubes) by adjusting the synthesizing parameters. The structure characterizations suggest that the Ag nanorods grow from the five-fold twinned decahedral crystal nuclei. The nature of the {l_brace}1 1 1{r_brace} planes of Ag crystal and the highly selective poly(vinylpyrollidone) adsorption on the {l_brace}100{r_brace} planes of Ag crystal nuclei are favourable for the formation of Ag nanorods and Ag nanowires. The single crystalline Ag nanocubes obtained at optimum conditions are perfect in shape and are enclosed by the {l_brace}1 0 0{r_brace} facets. The optical properties of the Ag nanostructures show an attractive plasma resonance, displaying a considerable dependence on the shape and size. The formation of the Ag nanostructures with well-defined shapes is probably due to the fact that the nanostructures are controlled thermodynamically and kinetically. The ability to generate shape-controlled Ag nanostructures also provides an opportunity to experimentally and systematically study the relationship between their properties and geometric shapes.

  12. Hydrothermal synthesis of nanostructured titania

    International Nuclear Information System (INIS)

    Yoshito, Walter Kenji; Ferreira, Nildemar A.M.; Rumbao, Ana Carolina S. Coutinho; Lazar, Dolores R.R.; Ussui, Valter

    2009-01-01

    Titania ceramics have many applications due to its surface properties and, recently, its nanostructured compounds, prepared by hydrothermal treatments, have been described to improve these properties. In this work, commercial titanium dioxide was treated with 10% sodium hydroxide solution in a pressurized reactor at 150°C for 24 hours under vigorous stirring and then washed following two different procedures. The first one consisted of washing with water and ethanol and the second with water and hydrochloric acid solution (1%). Resulting powders were characterized by X-ray diffraction, N 2 gas adsorption and field emission gun scanning and transmission electronic microscopy. Results showed that from an original starting material with mainly rutile phase, both anatase and H 2 Ti 3 O 7 phase could be identified after the hydrothermal treatment. Surface area of powders presented a notable increase of one order of magnitude and micrographs showed a rearrangement on the microstructure of powders. (author)

  13. Homoepitaxial Nanostructures of Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Tatiana V. Plakhova

    2015-01-01

    Full Text Available The homoepitaxial ZnO nanostructures (HENS were obtained on different substrates using various techniques. The first type of homoepitaxial ZnO nanorod arrays was grown on Si or ITO substrates by using two alternative sequences: (a seeding → growth from solution → growth from vapor and contrariwise (b seeding → growth from vapor → growth from solution. As follows from transport and cathode luminescence measurements homoepitaxial growth allows enhancing electrical or luminescence properties. The second type of HENS was prepared by growth of vertically or horizontally oriented ZnO nanorod arrays depending on monocrystalline ZnO wafers with [0001] and [10-10] orientation. In all cases the growth occurs along the c-axis of fast growth.

  14. Optical Characterization of Nanostructured Surfaces

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft

    Micro- and nanostructured surfaces are interesting due to the unique properties they add to the bulk material. One example is structural colors, where the interaction between surface structures and visible light produce bright color effects without the use of paints or dyes. Several research groups...... modeling to evaluate the dimensions of subwavelength gratings, by correlating the reflected light measured from the structures with a database of simulations. A new method is developed and termed color scatterometry, since compared to typical spectroscopic scatterometry, which evaluates the full reflection...... spectrum; the new method only evaluates the color of the reflected light using a standard RGB color camera. Color scatterometry provides the combined advantages of spectroscopic scatterometry, which provides fast evaluations, and imaging scatterometry that provides an overview image from which small...

  15. Hydrothermal synthesis of nanostructured titania

    International Nuclear Information System (INIS)

    Yoshito, W.K.; Ferreira, N.A.M.; Lazar, D.R.R.; Ussui, V.; Rumbao, A.C.S.

    2011-01-01

    Titania ceramics have many applications due to its surface properties and, recently, its nanostructured compounds, prepared by hydrothermal treatments, have been described to improve these properties. In this work, commercial titanium dioxide was treated with 10% sodium hydroxide solution in a pressurized reactor at 150 deg C for 24 hours under vigorous stirring and then washed following two different procedures. The first one consisted of washing with water and ethanol and the second with water and hydrochloric acid solution (1%). Resulting powders were characterized by X-ray diffraction, N 2 gas adsorption and field emission gun scanning and transmission electronic microscopy. Results showed that from an original starting material with mainly rutile phase, both anatase and H 2 Ti 3 O 7 phase could be identified after the hydrothermal treatment. Surface area of powders presented a notable increase of one order of magnitude and micrographs showed a rearrangement on the microstructure of powders. (author)

  16. Shape evolution of nanostructures by thermal and ion beam processing. Modeling and atomistic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Roentzsch, L.

    2007-07-01

    Single-crystalline nanostructures often exhibit gradients of surface (and/or interface) curvature that emerge from fabrication and growth processes or from thermal fluctuations. Thus, the system-inherent capillary force can initiate morphological transformations during further processing steps or during operation at elevated temperature. Therefore and because of the ongoing miniaturization of functional structures which causes a general rise in surface-to-volume ratios, solid-state capillary phenomena will become increasingly important: On the one hand diffusion-mediated capillary processes can be of practical use in view of non-conventional nanostructure fabrication methods based on self-organization mechanisms, on the other hand they can destroy the integrity of nanostructures which can go along with the failure of functionality. Additionally, capillarity-induced shape transformations are effected and can thereby be controlled by applied fields and forces (guided or driven evolution). With these prospects and challenges at hand, formation and shape transformation of single-crystalline nanostructures due to the system-inherent capillary force in combination with external fields or forces are investigated in the frame of this dissertation by means of atomistic computer simulations. For the exploration (search, description, and prediction) of reaction pathways of nanostructure shape transformations, kinetic Monte Carlo (KMC) simulations are the method of choice. Since the employed KMC code is founded on a cellular automaton principle, the spatio-temporal development of lattice-based N-particle systems (N up to several million) can be followed for time spans of several orders of magnitude, while considering local phenomena due to atomic-scale effects like diffusion, nucleation, dissociation, or ballistic displacements. In this work, the main emphasis is put on nanostructures which have a cylindrical geometry, for example, nanowires (NWs), nanorods, nanotubes etc

  17. Shape evolution of nanostructures by thermal and ion beam processing. Modeling and atomistic simulations

    International Nuclear Information System (INIS)

    Roentzsch, L.

    2007-01-01

    Single-crystalline nanostructures often exhibit gradients of surface (and/or interface) curvature that emerge from fabrication and growth processes or from thermal fluctuations. Thus, the system-inherent capillary force can initiate morphological transformations during further processing steps or during operation at elevated temperature. Therefore and because of the ongoing miniaturization of functional structures which causes a general rise in surface-to-volume ratios, solid-state capillary phenomena will become increasingly important: On the one hand diffusion-mediated capillary processes can be of practical use in view of non-conventional nanostructure fabrication methods based on self-organization mechanisms, on the other hand they can destroy the integrity of nanostructures which can go along with the failure of functionality. Additionally, capillarity-induced shape transformations are effected and can thereby be controlled by applied fields and forces (guided or driven evolution). With these prospects and challenges at hand, formation and shape transformation of single-crystalline nanostructures due to the system-inherent capillary force in combination with external fields or forces are investigated in the frame of this dissertation by means of atomistic computer simulations. For the exploration (search, description, and prediction) of reaction pathways of nanostructure shape transformations, kinetic Monte Carlo (KMC) simulations are the method of choice. Since the employed KMC code is founded on a cellular automaton principle, the spatio-temporal development of lattice-based N-particle systems (N up to several million) can be followed for time spans of several orders of magnitude, while considering local phenomena due to atomic-scale effects like diffusion, nucleation, dissociation, or ballistic displacements. In this work, the main emphasis is put on nanostructures which have a cylindrical geometry, for example, nanowires (NWs), nanorods, nanotubes etc

  18. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    Directory of Open Access Journals (Sweden)

    Zheng eRen

    2013-11-01

    Full Text Available This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  19. Nanostructures for Electrical Energy Storage (NEES) EFRC

    Data.gov (United States)

    Federal Laboratory Consortium — The Nanostructures for Electrical Energy Storage (NEES) EFRC is a multi-institutional research center, one of 46 Energy Frontier Research Centers established by the...

  20. Sulfated glycopeptide nanostructures for multipotent protein activation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungsoo S.; Fyrner, Timmy; Chen, Feng; Álvarez, Zaida; Sleep, Eduard; Chun, Danielle S.; Weiner, Joseph A.; Cook, Ralph W.; Freshman, Ryan D.; Schallmo, Michael S.; Katchko, Karina M.; Schneider, Andrew D.; Smith, Justin T.; Yun, Chawon; Singh, Gurmit; Hashmi, Sohaib Z.; McClendon, Mark T.; Yu, Zhilin; Stock, Stuart R.; Hsu, Wellington K.; Hsu, Erin L.; Stupp , Samuel I. (NWU)

    2017-06-19

    Biological systems have evolved to utilize numerous proteins with capacity to bind polysaccharides for the purpose of optimizing their function. A well-known subset of these proteins with binding domains for the highly diverse sulfated polysaccharides are important growth factors involved in biological development and tissue repair. We report here on supramolecular sulfated glycopeptide nanostructures, which display a trisulfated monosaccharide on their surfaces and bind five critical proteins with different polysaccharide-binding domains. Binding does not disrupt the filamentous shape of the nanostructures or their internal β-sheet backbone, but must involve accessible adaptive configurations to interact with such different proteins. The glycopeptide nanostructures amplified signalling of bone morphogenetic protein 2 significantly more than the natural sulfated polysaccharide heparin, and promoted regeneration of bone in the spine with a protein dose that is 100-fold lower than that required in the animal model. These highly bioactive nanostructures may enable many therapies in the future involving proteins.

  1. Metallic Nanostructures Based on DNA Nanoshapes

    Directory of Open Access Journals (Sweden)

    Boxuan Shen

    2016-08-01

    Full Text Available Metallic nanostructures have inspired extensive research over several decades, particularly within the field of nanoelectronics and increasingly in plasmonics. Due to the limitations of conventional lithography methods, the development of bottom-up fabricated metallic nanostructures has become more and more in demand. The remarkable development of DNA-based nanostructures has provided many successful methods and realizations for these needs, such as chemical DNA metallization via seeding or ionization, as well as DNA-guided lithography and casting of metallic nanoparticles by DNA molds. These methods offer high resolution, versatility and throughput and could enable the fabrication of arbitrarily-shaped structures with a 10-nm feature size, thus bringing novel applications into view. In this review, we cover the evolution of DNA-based metallic nanostructures, starting from the metallized double-stranded DNA for electronics and progress to sophisticated plasmonic structures based on DNA origami objects.

  2. Probing plasmonic nanostructures by photons and electrons

    DEFF Research Database (Denmark)

    Kneipp, Katrin; Kneipp, Harald; Kneipp, Janina

    2015-01-01

    We discuss recent developments for studying plasmonic metal nanostructures. Exploiting photons and electrons opens up new capabilities to probe the complete plasmon spectrum including bright and dark modes and related local optical fields at subnanometer spatial resolution. This comprehensive cha...

  3. Second harmonic spectroscopy of semiconductor nanostructures

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Yu, Ping; Bozhevolnyi, Sergey I.

    1999-01-01

    Semiconductor nanostructures and their application to optoelectronic devices have attracted much attention recently. Lower-dimensional structures, and in particular quantum dots, are highly anisotropic resulting in broken symmetry as compared to their bulk counterparts. This is not only reflected...

  4. Packaging glass with hierarchically nanostructured surface

    KAUST Repository

    He, Jr-Hau

    2017-08-03

    An optical device includes an active region and packaging glass located on top of the active region. A top surface of the packaging glass includes hierarchical nanostructures comprised of honeycombed nanowalls (HNWs) and nanorod (NR) structures extending from the HNWs.

  5. Nanostructuring steel for injection molding tools

    DEFF Research Database (Denmark)

    Al-Azawi, A.; Smistrup, Kristian; Kristensen, Anders

    2014-01-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography...... and ion beam etching are combined to nanostructure the planar surface of a steel wafer. Injection molded plastic parts with enhanced surface properties, like anti-reflective, superhydrophobic and structural colors can be achieved by micro-and nanostructuring the surface of the steel molds. We investigate...... the minimum line width that can be realized by our fabrication method and the influence of etching angle on the structure profile during the ion beam etching process. Trenches down to 400 nm in width have been successfully fabricated into a 316 type electro-polished steel wafer. Afterward a plastic replica...

  6. Packaging glass with hierarchically nanostructured surface

    KAUST Repository

    He, Jr-Hau; Fu, Hui-Chun

    2017-01-01

    An optical device includes an active region and packaging glass located on top of the active region. A top surface of the packaging glass includes hierarchical nanostructures comprised of honeycombed nanowalls (HNWs) and nanorod (NR) structures

  7. Plant-derived nanostructures: types and applications

    Science.gov (United States)

    Plant-derived nanostructures and nanoparticles (NPs) have functional applications in numerous disciplines such as health care, food and feed, cosmetics, biomedical science, energy science, drug-gene delivery, environmental health, and so on. Consequently, it is imperative for res...

  8. Chemical modifications and reactions in DNA nanostructures

    DEFF Research Database (Denmark)

    Gothelf, Kurt Vesterager

    2017-01-01

    such as hydrocarbons or steroids have been introduced to change the surface properties of DNA origami structures, either to protect the DNA nanostructure or to dock it into membranes and other hydrophobic surfaces. DNA nanostructures have also been used to control covalent chemical reactions. This article provides......DNA nanotechnology has the power to form self-assembled and well-defined nanostructures, such as DNA origami, where the relative positions of each atom are known with subnanometer precision. Our ability to synthesize oligonucleotides with chemical modifications in almost any desired position...... provides rich opportunity to incorporate molecules, biomolecules, and a variety of nanomaterials in specific positions on DNA nanostructures. Several standard modifications for oligonucleotides are available commercially, such as dyes, biotin, and chemical handles, and such modified oligonucleotides can...

  9. Hollow Micro-/Nanostructures: Synthesis and Applications

    KAUST Repository

    Lou, Xiong Wen (David); Archer, Lynden A.; Yang, Zichao

    2008-01-01

    for Portland cement, to produce concrete with enhanced strength and durability. This review is devoted to the progress made in the last decade in synthesis and applications of hollow micro-nanostructures. We present a comprehensive overview of synthetic

  10. Optical Biosensors Based on Semiconductor Nanostructures

    Directory of Open Access Journals (Sweden)

    Raúl J. Martín-Palma

    2009-06-01

    Full Text Available The increasing availability of semiconductor-based nanostructures with novel and unique properties has sparked widespread interest in their use in the field of biosensing. The precise control over the size, shape and composition of these nanostructures leads to the accurate control of their physico-chemical properties and overall behavior. Furthermore, modifications can be made to the nanostructures to better suit their integration with biological systems, leading to such interesting properties as enhanced aqueous solubility, biocompatibility or bio-recognition. In the present work, the most significant applications of semiconductor nanostructures in the field of optical biosensing will be reviewed. In particular, the use of quantum dots as fluorescent bioprobes, which is the most widely used application, will be discussed. In addition, the use of some other nanometric structures in the field of biosensing, including porous semiconductors and photonic crystals, will be presented.

  11. A novel nanostructure of cadmium oxide synthesized by mechanochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Tadjarodi, A., E-mail: tajarodi@iust.ac.ir [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Imani, M. [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of)

    2011-11-15

    Highlights: {yields} A novel nanostructure of CdO was synthesized by mechanochemical reaction followed by calcination. {yields} Mechanochemical method is a simple and low-cost to synthesize nanomaterials. {yields} The obtained precursor was characterized by FT-IR, NMR techniques and elemental analysis. {yields} SEM images showed cauliflower-like shape of sample with components average diameter of 68 nm. {yields} The rods and tubes bundles with single crystalline nature were revealed by ED pattern and TEM images. -- Abstract: Cauliflower-like cadmium oxide (CdO) nanostructure was synthesized by mechanochemical reaction followed calcination procedure. Cadmium acetate dihydrate and acetamide were used as reagents and the resulting precursor was calcinated at 450 {sup o}C for 2 h in air. The structures of the precursor and resultant product of the heating treatment were characterized using Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and elemental analysis, X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction pattern (ED). SEM and TEM images revealed the cauliflower-like morphology of the sample. This structure includes the bundles of rods and tubes in nanoscale, which combine with each other and form the resulting morphology with the average diameter, 68 nm of the components. ED pattern indicated the single crystal nature of the formed bundles.

  12. A novel nanostructure of cadmium oxide synthesized by mechanochemical method

    International Nuclear Information System (INIS)

    Tadjarodi, A.; Imani, M.

    2011-01-01

    Highlights: → A novel nanostructure of CdO was synthesized by mechanochemical reaction followed by calcination. → Mechanochemical method is a simple and low-cost to synthesize nanomaterials. → The obtained precursor was characterized by FT-IR, NMR techniques and elemental analysis. → SEM images showed cauliflower-like shape of sample with components average diameter of 68 nm. → The rods and tubes bundles with single crystalline nature were revealed by ED pattern and TEM images. -- Abstract: Cauliflower-like cadmium oxide (CdO) nanostructure was synthesized by mechanochemical reaction followed calcination procedure. Cadmium acetate dihydrate and acetamide were used as reagents and the resulting precursor was calcinated at 450 o C for 2 h in air. The structures of the precursor and resultant product of the heating treatment were characterized using Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and elemental analysis, X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction pattern (ED). SEM and TEM images revealed the cauliflower-like morphology of the sample. This structure includes the bundles of rods and tubes in nanoscale, which combine with each other and form the resulting morphology with the average diameter, 68 nm of the components. ED pattern indicated the single crystal nature of the formed bundles.

  13. Leafy nanostructure PANI for material of supercapacitors

    OpenAIRE

    XI Dong; CHEN Xinman

    2013-01-01

    Nanostructure conducting polyaniline(PANI) has great potential applications in supercapacitor electrode materials.In this paper,we report a template-free approach to synthesize PANI by a galvanostatic current procedure with a three-electrode configuration directly on indium-doped tin-oxide substrates (ITO).The morphology of product was characterized by Hitachi S-4800 field emission scanning electron microscope (FE-SEM).Due to the nanostructure,the specific capacitance of PANI film with the th...

  14. Directed spatial organization of zinc oxide nanostructures

    Science.gov (United States)

    Hsu, Julia [Albuquerque, NM; Liu, Jun [Richland, WA

    2009-02-17

    A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

  15. Engineering metallic nanostructures for plasmonics and nanophotonics

    Science.gov (United States)

    Lindquist, Nathan C.; Nagpal, Prashant; McPeak, Kevin M.; Norris, David J.; Oh, Sang-Hyun

    2012-03-01

    Metallic nanostructures now play an important role in many applications. In particular, for the emerging fields of plasmonics and nanophotonics, the ability to engineer metals on nanometric scales allows the development of new devices and the study of exciting physics. This review focuses on top-down nanofabrication techniques for engineering metallic nanostructures, along with computational and experimental characterization techniques. A variety of current and emerging applications are also covered.

  16. Gold nanostructures and methods of use

    Science.gov (United States)

    Zhang, Jin Z [Santa Cruz, CA; Schwartzberg, Adam [Santa Cruz, CA; Olson, Tammy Y [Santa Cruz, CA

    2012-03-20

    The invention is drawn to novel nanostructures comprising hollow nanospheres and nanotubes for use as chemical sensors, conduits for fluids, and electronic conductors. The nanostructures can be used in microfluidic devices, for transporting fluids between devices and structures in analytical devices, for conducting electrical currents between devices and structure in analytical devices, and for conducting electrical currents between biological molecules and electronic devices, such as bio-microchips.

  17. Condensation on Superhydrophobic Copper Oxide Nanostructures

    OpenAIRE

    Enright, Ryan; Miljkovic, Nenad; Dou, Nicholas; Nam, Youngsuk; Wang, Evelyn N.

    2013-01-01

    Condensation is an important process in both emerging and traditional power generation and water desalination technologies. Superhydrophobic nanostructures promise enhanced condensation heat transfer by reducing the characteristic size of departing droplets via a surface-tension-driven mechanism [1]. In this work, we investigated a scalable synthesis technique to produce oxide nanostructures on copper surfaces capable of sustaining superhydrophobic condensation and characterized the growth an...

  18. Nanostructure symmetry: Relevance for physics and computing

    International Nuclear Information System (INIS)

    Dupertuis, Marc-André; Oberli, D. Y.; Karlsson, K. F.; Dalessi, S.; Gallinet, B.; Svendsen, G.

    2014-01-01

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented

  19. Nanostructure symmetry: Relevance for physics and computing

    Energy Technology Data Exchange (ETDEWEB)

    Dupertuis, Marc-André; Oberli, D. Y. [Laboratory for Physics of Nanostructure, EPF Lausanne (Switzerland); Karlsson, K. F. [Department of Physics, Chemistry, and Biology (IFM), Linköping University (Sweden); Dalessi, S. [Computational Biology Group, Department of Medical Genetics, University of Lausanne (Switzerland); Gallinet, B. [Nanophotonics and Metrology Laboratory, EPF Lausanne (Switzerland); Svendsen, G. [Dept. of Electronics and Telecom., Norwegian University of Science and Technology, Trondheim (Norway)

    2014-03-31

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented.

  20. Nanostructured gold microelectrodes for extracellular recording

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, Dorothea; Wolfrum, Bernhard; Maybeck, Vanessa; Offenhaeusser, Andreas [CNI Center of Nanoelectronic Systems for Information Technology and Institute of Bio- and Nanosystems 2, Forschungszentrum Juelich (Germany)

    2010-07-01

    Electrophysiological activity of electrogenic cells is currently recorded with planar bioelectronic interfaces such as microelectrode arrays (MEAs). In this work, a novel concept of biocompatible nanostructured gold MEAs for extracellular signal recording is presented. MEAs were fabricated using clean room technologies, e.g. photolithography and metallization. Subsequently, they were modified with gold nanopillars of approximately 300 to 400 nm in height and 60 nm width. The nanostructuring process was carried out with a template-assisted approach using nanoporous aluminium oxide. Impedance spectroscopy of the resulting nanostructures showed higher capacitances compared to planar gold. This confirmed the expected increase of the surface area via nanostructuring. We used the nanostructured microelectrodes to record extracellular potentials from heart muscle cells (HL1), which were plated onto the chips. Good coupling between the HL1 cells and the nanostructured electrodes was observed. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In future applications this nanopillar concept can be adopted for distinct interface materials and coupling to cellular and molecular sensing components.

  1. Contribution of double scattering to structural coloration in quasiordered nanostructures of bird feathers

    Science.gov (United States)

    Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O.; Mochrie, Simon G. J.; Dufresne, Eric R.; Cao, Hui

    2010-05-01

    We measured the polarization- and angle-resolved optical scattering and reflection spectra of the quasiordered nanostructures in the bird feather barbs. In addition to the primary peak that originates from single scattering, we observed a secondary peak which exhibits depolarization and distinct angular dispersion. We explained the secondary peak in terms of double scattering, i.e., light is scattered successively twice by the structure. The two sequential single-scattering events are considered uncorrelated. Using the Fourier power spectra of the nanostructures obtained from the small-angle x-ray scattering experiment, we calculated the double scattering of light in various directions. The double-scattering spectrum is broader than the single-scattering spectrum, and it splits into two subpeaks at larger scattering angle. The good agreement between the simulation results and the experimental data confirms that double scattering of light makes a significant contribution to the structural color.

  2. Contribution of double scattering to structural coloration in quasiordered nanostructures of bird feathers

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O.; Mochrie, Simon G.J.; Dufresne, Eric R.; Cao, Hui (Yale)

    2010-07-28

    We measured the polarization- and angle-resolved optical scattering and reflection spectra of the quasiordered nanostructures in the bird feather barbs. In addition to the primary peak that originates from single scattering, we observed a secondary peak which exhibits depolarization and distinct angular dispersion. We explained the secondary peak in terms of double scattering, i.e., light is scattered successively twice by the structure. The two sequential single-scattering events are considered uncorrelated. Using the Fourier power spectra of the nanostructures obtained from the small-angle x-ray scattering experiment, we calculated the double scattering of light in various directions. The double-scattering spectrum is broader than the single-scattering spectrum, and it splits into two subpeaks at larger scattering angle. The good agreement between the simulation results and the experimental data confirms that double scattering of light makes a significant contribution to the structural color.

  3. Commercial Implementation of Model-Based Manufacturing of Nanostructured Metals

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, Terry C. [Los Alamos National Laboratory

    2012-07-24

    Computational modeling is an essential tool for commercial production of nanostructured metals. Strength is limited by imperfections at the high strength levels that are achievable in nanostructured metals. Processing to achieve homogeneity at the micro- and nano-scales is critical. Manufacturing of nanostructured metals is intrinsically a multi-scale problem. Manufacturing of nanostructured metal products requires computer control, monitoring and modeling. Large scale manufacturing of bulk nanostructured metals by Severe Plastic Deformation is a multi-scale problem. Computational modeling at all scales is essential. Multiple scales of modeling must be integrated to predict and control nanostructural, microstructural, macrostructural product characteristics and production processes.

  4. Synergistically Enhanced Performance of Ultrathin Nanostructured Silicon Solar Cells Embedded in Plasmonically Assisted, Multispectral Luminescent Waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung-Min; Dhar, Purnim; Chen, Huandong; Montenegro, Angelo; Liaw, Lauren; Kang, Dongseok; Gai, Boju; Benderskii, Alexander V.; Yoon, Jongseung

    2017-04-12

    Ultrathin silicon solar cells fabricated by anisotropic wet chemical etching of single-crystalline wafer materials represent an attractive materials platform that could provide many advantages for realizing high-performance, low-cost photovoltaics. However, their intrinsically limited photovoltaic performance arising from insufficient absorption of low-energy photons demands careful design of light management to maximize the efficiency and preserve the cost-effectiveness of solar cells. Herein we present an integrated flexible solar module of ultrathin, nanostructured silicon solar cells capable of simultaneously exploiting spectral upconversion and downshifting in conjunction with multispectral luminescent waveguides and a nanostructured plasmonic reflector to compensate for their weak optical absorption and enhance their performance. The 8 μm-thick silicon solar cells incorporating a hexagonally periodic nanostructured surface relief are surface-embedded in layered multispectral luminescent media containing organic dyes and NaYF4:Yb3+,Er3+ nanocrystals as downshifting and upconverting luminophores, respectively, via printing-enabled deterministic materials assembly. The ultrathin nanostructured silicon microcells in the composite luminescent waveguide exhibit strongly augmented photocurrent (~40.1 mA/cm2) and energy conversion efficiency (~12.8%) than devices with only a single type of luminescent species, owing to the synergistic contributions from optical downshifting, plasmonically enhanced upconversion, and waveguided photon flux for optical concentration, where the short-circuit current density increased by ~13.6 mA/cm2 compared with microcells in a nonluminescent medium on a plain silver reflector under a confined illumination.

  5. Single-molecule chemical reactions on DNA origami

    DEFF Research Database (Denmark)

    Voigt, Niels Vinther; Tørring, Thomas; Rotaru, Alexandru

    2010-01-01

    as templates for building materials with new functional properties. Relatively large nanocomponents such as nanoparticles and biomolecules can also be integrated into DNA nanostructures and imaged. Here, we show that chemical reactions with single molecules can be performed and imaged at a local position...... on a DNA origami scaffold by atomic force microscopy. The high yields and chemoselectivities of successive cleavage and bond-forming reactions observed in these experiments demonstrate the feasibility of post-assembly chemical modification of DNA nanostructures and their potential use as locally......DNA nanotechnology and particularly DNA origami, in which long, single-stranded DNA molecules are folded into predetermined shapes, can be used to form complex self-assembled nanostructures. Although DNA itself has limited chemical, optical or electronic functionality, DNA nanostructures can serve...

  6. Synthesis, morphology, optical and photocatalytic performance of nanostructured β-Ga{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Girija, K. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); DRDO – BU CLS, Bharathiar University, Coimbatore 641046 (India); Thirumalairajan, S. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Avadhani, G.S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Ponpandian, N. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); DRDO – BU CLS, Bharathiar University, Coimbatore 641046 (India); Viswanathan, C. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India)

    2013-06-01

    Highlights: ► Nanostructures of β-Ga{sub 2}O{sub 3} were prepared using facile reflux condensation process. ► The pH of the reaction mixture shows evident influence on the size and shape of the nanostructures formed. ► The nanostructures exhibited good photocatalytic activity toward Rhodamine B and was found to be superior for higher pH value. - Abstract: Fine powders of β-Ga{sub 2}O{sub 3} nanostructures were prepared via low temperature reflux condensation method by varying the pH value without using any surfactant. The pH value of reaction mixture had great influence on the morphology of final products. High crystalline single phase β-Ga{sub 2}O{sub 3} nanostructures were obtained by thermal treatment at 900 °C which was confirmed by X-ray diffraction and Raman spectroscopy. The morphological analysis revealed rod like nanostructures at lower and higher pH values of 6 and 10, while spindle like structures were obtained at pH = 8. The phase purity and presence of vibrational bands were identified using Fourier transform infrared spectroscopy. The optical absorbance spectrum showed intense absorption features in the UV spectral region. A broad blue emission peak centered at 441 nm due to donor–acceptor gallium–oxygen vacancy pair recombination appeared. The photocatalytic activity toward Rhodamine B under visible light irradiation was higher for nanorods at pH 10.

  7. New nanostructured nickel–polymer nanohybrids with improved surface hydrophobicity and effect on the living cells adhesion

    International Nuclear Information System (INIS)

    Macko, Ján; Oriňak, Andrej; Oriňaková, Renáta; Muhmann, Christian; Petruš, Ondrej; Harvanová, Denisa

    2015-01-01

    Highlights: • Unique nanohybrid formed from nanostructured nickel covered with polymer layer in being introduced. • Polymer is spin-coated on nanostructured nickel surface. • Nanohybrid surface hydrophobicity extension has been observed. • Adhesion of the cells was studied at nanohybrid surface. • The cells growth was differently inhibited at nanohybrid surface. - Abstract: An intensive gain of surface hydrophobicity has been observed on the differently polar polymer layers spin-coated directly on the previously prepared nanostructured nickel surface to form nanohybrids. Nanostructured nickel layer has been prepared by electrochemical deposition to form polyhedral crystalline nanostructure. Surface morphology and homogeneity of a nanohybrid polymer layer have been monitored by TOF-SIMS and SEM methods. Hydrophobicity extension of nanohybrid surfaces increased nearly linearly with decreasing polarity of single polymers applied and maximum increase in hydrophobicity value obtained was 32%. Novel nanohybrid surfaces functionality has been tested on the different cells adhesion. The results showed cell adhesion followed with an inhibition of the living cells spreading and proliferation on declared nanostructured nickel–polymer nanohybrid surfaces. The maximum inhibition activity of nanohybrid surface against cells line has been observed in a case when polydimethylsiloxane was applied as surface polymeric layer. Preparation of this kind of surface is easy and inexpensive, with many proposed applications where hydrophobic surfaces are required. This also can tend as a model for the preparation of the surfaces with cell anti-adhesion and antimicrobial activity.

  8. Antibacterial efficacy of core-shell nanostructures encapsulating gentamicin against an in vivo intracellular  Salmonella model

    Directory of Open Access Journals (Sweden)

    Ashish Ranjan

    2009-12-01

    Full Text Available Ashish Ranjan1, Nikorn Pothayee2,3, Mohammed N Seleem2, Ronald D Tyler Jr4, Bonnie Brenseke4, Nammalwar Sriranganathan2,4, Judy S Riffle2,3, Ramanathan Kasimanickam11Department of Large Animal Clinical Sciences, 2Institute for Critical Technology and Applied Science, 3Macromolecules and Interfaces Institute, 4Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VAAbstract: Pluronic based core-shell nanostructures encapsulating gentamicin were designed in this study. Block copolymers of (PAA–+Na-b-(PEO-b-PPO-b-PEO-b-PAA– +Na were blended with PAA– Na+ and complexed with the polycationic antibiotic gentamicin to form nanostructures. Synthesized nanostructures had a hydrodynamic diameter of 210 nm, zeta potentials of –0.7 (±0.2, and incorporated ~20% by weight of gentamicin. Nanostructures upon co-incubation with J774A.1 macrophage cells showed no adverse toxicity in vitro. Nanostructures administered in vivo either at multiple dosage of 5 µg g–1 or single dosage of 15 µg g–1 in AJ-646 mice infected with Salmonella resulted in significant reduction of viable bacteria in the liver and spleen. Histopathological evaluation for concentration-dependent toxicity at a dosage of 15 µg g–1 revealed mineralized deposits in 50% kidney tissues of free gentamicin-treated mice which in contrast was absent in nanostructure-treated mice. Thus, encapsulation of gentamicin in nanostructures may reduce toxicity and improve in vivo bacterial clearance.Keywords: gentamicin, core-shell nanostructures, Salmonella

  9. Nano-soldering to single atomic layer

    Science.gov (United States)

    Girit, Caglar O [Berkeley, CA; Zettl, Alexander K [Kensington, CA

    2011-10-11

    A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

  10. Single-mode biological distributed feedback laser

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Maier-Flaig, Florian; Lemmer, Uli

    2013-01-01

    Single-mode second order distributed feedback (DFB) lasers of riboflavin (vitamin B2) doped gelatine films on nanostructured low refractive index material are demonstrated. Manufacturing is based on a simple UV nanoimprint and spin-coating. Emission wavelengths of 543 nm and 562 nm for two...

  11. Method for manufacturing a single crystal nanowire

    NARCIS (Netherlands)

    van den Berg, Albert; Bomer, Johan G.; Carlen, Edwin; Chen, S.; Kraaijenhagen, Roderik Adriaan; Pinedo, Herbert Michael

    2013-01-01

    A method for manufacturing a single crystal nano-structure is provided comprising the steps of providing a device layer with a 100 structure on a substrate; providing a stress layer onto the device layer; patterning the stress layer along the 110 direction of the device layer; selectively removing

  12. Method for manufacturing a single crystal nanowire

    NARCIS (Netherlands)

    van den Berg, Albert; Bomer, Johan G.; Carlen, Edwin; Chen, S.; Kraaijenhagen, R.A.; Pinedo, Herbert Michael

    2010-01-01

    A method for manufacturing a single crystal nano-structure is provided comprising the steps of providing a device layer with a 100 structure on a substrate; providing a stress layer onto the device layer; patterning the stress layer along the 110 direction of the device layer; selectively removing

  13. Plastic deformation of indium nanostructures

    International Nuclear Information System (INIS)

    Lee, Gyuhyon; Kim, Ju-Young; Burek, Michael J.; Greer, Julia R.; Tsui, Ting Y.

    2011-01-01

    Highlights: → Indium nanopillars display two different deformation mechanisms. → ∼80% exhibited low flow stresses near that of bulk indium. → Low strength nanopillars have strain rate sensitivity similar to bulk indium. → ∼20% of compressed indium nanopillars deformed at nearly theoretical strengths. → Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.

  14. Semiconductor nanostructures for artificial photosynthesis

    Science.gov (United States)

    Yang, Peidong

    2012-02-01

    Nanowires, with their unique capability to bridge the nanoscopic and macroscopic worlds, have already been demonstrated as important materials for different energy conversion. One emerging and exciting direction is their application for solar to fuel conversion. The generation of fuels by the direct conversion of solar energy in a fully integrated system is an attractive goal, but no such system has been demonstrated that shows the required efficiency, is sufficiently durable, or can be manufactured at reasonable cost. One of the most critical issues in solar water splitting is the development of a suitable photoanode with high efficiency and long-term durability in an aqueous environment. Semiconductor nanowires represent an important class of nanostructure building block for direct solar-to-fuel application because of their high surface area, tunable bandgap and efficient charge transport and collection. Nanowires can be readily designed and synthesized to deterministically incorporate heterojunctions with improved light absorption, charge separation and vectorial transport. Meanwhile, it is also possible to selectively decorate different oxidation or reduction catalysts onto specific segments of the nanowires to mimic the compartmentalized reactions in natural photosynthesis. In this talk, I will highlight several recent examples in this lab using semiconductor nanowires and their heterostructures for the purpose of direct solar water splitting.

  15. Chemical scissors cut phosphorene nanostructures

    International Nuclear Information System (INIS)

    Peng, Xihong; Wei, Qun

    2014-01-01

    Phosphorene, a recently fabricated two-dimensional puckered honeycomb structure of phosphorus, showed promising properties for applications in nano-electronics. In this work, we report a chemical scissors effect on phosphorene, using first-principles method. It was found that chemical species, such as H, OH, F, and Cl, can act as scissors to cut phosphorene. Phosphorus nanochains and nanoribbons can be obtained. The scissors effect results from the strong bonding between the chemical species and phosphorus atoms. Other species such as O, S and Se fail to cut phosphorene nanostructures due to their weak bonding with phosphorus. The electronic structures of the produced P-chains reveal that the hydrogenated chain is an insulator while the pristine chain is a one-dimensional Dirac material, in which the charge carriers are massless fermions travelling at an effective speed of light ∼8 × 10 5 m s −1 . The obtained zigzag phosphorene nanoribbons show either metallic or semiconducting behaviors, depending on the treatment of the edge phosphorus atoms. (paper)

  16. Facile Growth of Multi-twined Au Nanostructures

    Indian Academy of Sciences (India)

    like nanostructures undergo spontaneous transformation into multi-twined nanostructures within 24 h. These nanocrystalline ... reactions,1 and a color indicating reagent for the sensing of biomolecules.2 ... Two-compartment, three electrode ...

  17. Mapping the nanostructures in human adult and baby tooth enamel

    International Nuclear Information System (INIS)

    Low, I.M.; Mahmood, U.; Duraman, N.

    2005-01-01

    This paper investigates and compares the variations in crystal structure, composition, and nanostructures within the human adult and deciduous teeth. The similarities and differences in the nanostructure of both types of teeth are highlighted and discussed. (author)

  18. Terminating DNA Tile Assembly with Nanostructured Caps.

    Science.gov (United States)

    Agrawal, Deepak K; Jiang, Ruoyu; Reinhart, Seth; Mohammed, Abdul M; Jorgenson, Tyler D; Schulman, Rebecca

    2017-10-24

    Precise control over the nucleation, growth, and termination of self-assembly processes is a fundamental tool for controlling product yield and assembly dynamics. Mechanisms for altering these processes programmatically could allow the use of simple components to self-assemble complex final products or to design processes allowing for dynamic assembly or reconfiguration. Here we use DNA tile self-assembly to develop general design principles for building complexes that can bind to a growing biomolecular assembly and terminate its growth by systematically characterizing how different DNA origami nanostructures interact with the growing ends of DNA tile nanotubes. We find that nanostructures that present binding interfaces for all of the binding sites on a growing facet can bind selectively to growing ends and stop growth when these interfaces are presented on either a rigid or floppy scaffold. In contrast, nucleation of nanotubes requires the presentation of binding sites in an arrangement that matches the shape of the structure's facet. As a result, it is possible to build nanostructures that can terminate the growth of existing nanotubes but cannot nucleate a new structure. The resulting design principles for constructing structures that direct nucleation and termination of the growth of one-dimensional nanostructures can also serve as a starting point for programmatically directing two- and three-dimensional crystallization processes using nanostructure design.

  19. Nanostructuring steel for injection molding tools

    International Nuclear Information System (INIS)

    Al-Azawi, A; Smistrup, K; Kristensen, A

    2014-01-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography and ion beam etching are combined to nanostructure the planar surface of a steel wafer. Injection molded plastic parts with enhanced surface properties, like anti-reflective, superhydrophobic and structural colors can be achieved by micro- and nanostructuring the surface of the steel molds. We investigate the minimum line width that can be realized by our fabrication method and the influence of etching angle on the structure profile during the ion beam etching process. Trenches down to 400 nm in width have been successfully fabricated into a 316 type electro-polished steel wafer. Afterward a plastic replica has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items, are produced. (paper)

  20. Nanostructured Thin Film Synthesis by Aerosol Chemical Vapor Deposition for Energy Storage Applications

    Science.gov (United States)

    Chadha, Tandeep S.

    Renewable energy sources offer a viable solution to the growing energy demand while mitigating concerns for greenhouse gas emissions and climate change. This has led to a tremendous momentum towards solar and wind-based energy harvesting technologies driving efficiencies higher and costs lower. However, the intermittent nature of these energy sources necessitates energy storage technologies, which remain the Achilles heel in meeting the renewable energy goals. This dissertation focusses on two approaches for addressing the needs of energy storage: first, targeting direct solar to fuel conversion via photoelectrochemical water-splitting and second, improving the performance of current rechargeable batteries by developing new electrode architectures and synthesis processes. The aerosol chemical vapor deposition (ACVD) process has emerged as a promising single-step approach for nanostructured thin film synthesis directly on substrates. The relationship between the morphology and the operating parameters in the process is complex. In this work, a simulation based approach has been developed to understand the relationship and acquire the ability of predicting the morphology. These controlled nanostructured morphologies of TiO2 , compounded with gold nanoparticles of various shapes, are used for solar water-splitting applications. Tuning of light absorption in the visible-light range along with reduced electron-hole recombination in the composite structures has been demonstrated. The ACVD process is further extended to a novel single-step synthesis of nanostructured TiO2 electrodes directly on the current collector for applications as anodes in lithium-ion batteries, mainly for electric vehicles and hybrid electric vehicles. The effect of morphology of the nanostructures has been investigated via experimental studies and electrochemical transport modelling. Results demonstrate the exceptional performance of the single crystal one-dimensional nanostructures over granular

  1. Micro-/nanostructured multicomponent molecular materials: design, assembly, and functionality.

    Science.gov (United States)

    Yan, Dongpeng

    2015-03-23

    Molecule-based micro-/nanomaterials have attracted considerable attention because their properties can vary greatly from the corresponding macro-sized bulk systems. Recently, the construction of multicomponent molecular solids based on crystal engineering principles has emerged as a promising alternative way to develop micro-/nanomaterials. Unlike single-component materials, the resulting multicomponent systems offer the advantages of tunable composition, and adjustable molecular arrangement, and intermolecular interactions within their solid states. The study of these materials also supplies insight into how the crystal structure, molecular components, and micro-/nanoscale effects can influence the performance of molecular materials. In this review, we describe recent advances and current directions in the assembly and applications of crystalline multicomponent micro-/nanostructures. Firstly, the design strategies for multicomponent systems based on molecular recognition and crystal engineering principles are introduced. Attention is then focused on the methods of fabrication of low-dimensional multicomponent micro-/nanostructures. Their new applications are also outlined. Finally, we briefly discuss perspectives for the further development of these molecular crystalline micro-/nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Controlling the flux dynamics in superconductors by nanostructured magnetic arrays

    Science.gov (United States)

    Kapra, Andrey

    In this thesis we investigate theoretically how the critical current jc of nano-engineered mesoscopic superconducting film can be improved and how one can control the dynamics of the magnetic flux, e.g., the transition from flux-pinned to flux-flow regime, using arrays of magnetic nanostructures. In particularly we investigate: (1) Vortex transport phenomena in superconductors with deposited ferromagnetic structures on top, and the influence of the sample geometry on the critical parameters and on the vortex configurations. Changing geometry of the magnetic bars and magnetization of the bars will affect the critical current jc of the superconducting film. Such nanostructured ferromagnets strongly alter the vortex structure in its neighborhood. The influence of geometry, position and magnetization of the ferromagnet (single bar or regular lattice of the bars) on the critical parameters of the superconductor is investigated. (2) Effect of flux confinement in narrow superconducting channels with zigzag-shaped banks: the flux motion is confined in the transverse (perpendicular) direction of a diamond-cell-shape channel. The matching effect for the magnetic flux is found in the system relevantless of boundary condition. We discuss the dynamics of vortices in the samples and vortex pattern formation in the channel. We show how the inclusion of higher-Tc superconductor into the sample can lead to enhanced properties of the system. By adding an external driving force, we study the vortex dynamics. The different dynamic regimes are discussed. They allowed an effective control of magnetic flux in superconductors.

  3. Plasmonics of magnetic and topological graphene-based nanostructures

    Science.gov (United States)

    Kuzmin, Dmitry A.; Bychkov, Igor V.; Shavrov, Vladimir G.; Temnov, Vasily V.

    2018-02-01

    Graphene is a unique material in the study of the fundamental limits of plasmonics. Apart from the ultimate single-layer thickness, its carrier concentration can be tuned by chemical doping or applying an electric field. In this manner, the electrodynamic properties of graphene can be varied from highly conductive to dielectric. Graphene supports strongly confined, propagating surface plasmon polaritons (SPPs) in a broad spectral range from terahertz to mid-infrared frequencies. It also possesses a strong magneto-optical response and thus provides complimentary architectures to conventional magneto-plasmonics based on magneto-optically active metals or dielectrics. Despite a large number of review articles devoted to plasmonic properties and applications of graphene, little is known about graphene magneto-plasmonics and topological effects in graphene-based nanostructures, which represent the main subject of this review. We discuss several strategies to enhance plasmonic effects in topologically distinct closed surface landscapes, i.e. graphene nanotubes, cylindrical nanocavities and toroidal nanostructures. A novel phenomenon of the strongly asymmetric SPP propagation on chiral meta-structures and the fundamental relations between structural and plasmonic topological indices are reviewed.

  4. Device Fabrication and Probing of Discrete Carbon Nanostructures

    KAUST Repository

    Batra, Nitin M

    2015-05-06

    Device fabrication on multi walled carbon nanotubes (MWCNTs) using electrical beam lithography (EBL), electron beam induced deposition (EBID), ion beam induced deposition (IBID) methods was carried out, followed by device electrical characterization using a conventional probe station. A four-probe configuration was utilized to measure accurately the electrical resistivity of MWCNTs with similar results obtained from devices fabricated by different methods. In order to reduce the contact resistance of the beam deposited platinum electrodes, single step vacuum thermal annealing was performed. Microscopy and spectroscopy were carried out on the beam deposited electrodes to follow the structural and chemical changes occurring during the vacuum thermal annealing. For the first time, a core-shell type structure was identified on EBID Pt and IBID Pt annealed electrodes and analogous free standing nanorods previously exposed to high temperature. We believe this observation has important implications for transport properties studies of carbon materials. Apart from that, contamination of carbon nanostructure, originating from the device fabrication methods, was also studied. Finally, based on the observations of faster processing time together with higher yield and flexibility for device preparation, we investigated EBID to fabricate devices for other discrete carbon nanostructures.

  5. Amorphous nanostructuralization in HOPG by 1014 W cm-2 laser

    International Nuclear Information System (INIS)

    NISHIMURA, Yasuhiko; KITAGAWA, Yoneyoshi; MORI, Yoshitaka; ISHII, Katsuhiro; HANAYAMA, Ryohei; AZUMA, Hirozumi; HIOKI, Tatsumi; MOTOHIRO, Tomoyoshi; NISHI, Teppei; KOMEDA, Osamu; SEKINE, Takashi; SATO, Nakahiro; KURITA, Takashi; KAWASHIMA, Toshiyuki; KAN, Hirofumi; SUNAHARA, Atsushi; SENTOKU, Yasuhiko; MIURA, Eisuke

    2016-01-01

    This reports provide an amorphous nanostructuralization technique on the surface modification in Highly Oriented Pyrolytic Graphite (HOPG) by using a femtosecond laser. We showed, for the first time, that the surface of HOPG is changed to the amorphous nanostructuralization graphite by using a femtosecond laser-driven compression technique. Our results also suggest that the HOPG surface is changed until the deeper area from the surface by the laser-driven shock wave. A single shot of a femtosecond laser beam (1.27 ∼ 1.33×10 14 Wcm∼ 2 in intensity, with 2 mm-diameter, and 110 fs in pulse width) is irradiated under the vacuum ambience onto a 2 mm-thick of HOPG. The calculated impact pressures on a sample was 8.3 ∼ 8.7 GPa. Crystal structure in the HOPG were analyzed using a Raman spectroscopy and an X-ray diffraction, those analyzing depth from the surface were 50 nm and 350 μm, respectively. (paper)

  6. Hybrid Nanostructures Containing Sulfadiazine Modified Chitosan as Antimicrobial Drug Carriers

    Directory of Open Access Journals (Sweden)

    Bogdanel Silvestru Munteanu

    2016-11-01

    Full Text Available Chitosan (CH nanofibrous structures containing sulfadiazine (SDZ or sulfadiazine modified chitosan (SCH in the form of functional nanoparticles attached to nanofibers (hybrid nanostructures were obtained by mono-axial and coaxial electrospinning. The mono-axial design consisted of a SDZ/CH mixture solution fed through a single nozzle while the coaxial design consisted of SCH and CH solutions separately supplied to the inner and outer nozzle (or in reverse order. The CH ability to form nanofibers assured the formation of a nanofiber mesh, while SDZ and SCH, both in form of suspensions in the electrospun solution, assured the formation of active nanoparticles which remained attached to the CH nanofiber mesh after the electrospinning process. The obtained nanostructures were morphologically characterized by scanning electron microscopy (SEM and atomic force microscopy (AFM. The SDZ release profiles and kinetics were analyzed. The SDZ or SCH nanoparticles loosely attached at the surface of the nanofibers, provide a burst release in the first 20 min, which is important to stop the possible initial infection in a wound, while the SDZ and SCH from the nanoparticles which are better confined (or even encapsulated into the CH nanofibers would be slowly released with the erosion/disruption of the CH nanofiber mesh.

  7. Carbon nanostructure formation driven by energetic particles

    International Nuclear Information System (INIS)

    Zhu Zhiyuan; Gong Jinlong; Zhu Dezhang

    2006-01-01

    Carbon nanostructures, especially carbon nanotubes (CNTs), have been envisaged to be the building blocks of a variety of nanoscale devices and materials. The inherent nanometer-size and ability of being either metallic or semiconductive of CNTs lead to their application in nanoelectronics. Excellent mechanical characteristics of CNTs suggest their use as structural reinforcements. However, to fully exploit the potential applications, effective means of tailoring CNT properties must be developed. Irradiation of materials with energetic particles beams (ions and electrons) is a standard and important tool for modifying material properties. Irradiation makes it possible to dope the samples, to create local amorphous region or vice versa, recrystallize the lattice and even drive a phase transition. In this paper, we report our results of (1) phase transfromation from carbon nanotubes to nanocrystalline diamond driven by hydrogen plasma, (2) onion-like nanostructure from carbon nanotubes driven by ion beams of several tens keV, and (3) amorphous carbon nanowire network formation by ion beam irradiation. Structural phase transformation from multiwalled carbon nanotubes to nanocrystalline diamond by hydrogen plasma post-treatment was carried out. Ultrahigh equivalent diamond nucleation density of more than 1011 nuclei/cm 2 was obtained. The diamond formation and growth mechanisms were proposed to be the consequence of the formation of sp3 bonded amorphous carbon clusters. The hydrogen chemisorption on curved graphite network and the energy deposited on CNTs by continuous impingement of activated molecular or atomic hydrogen are responsible for the formation of amorphous carbon matrix. Diamond nucleates and grows in the way similar to that of diamond chemical vapor deposition processes on amorphous carbon films. Furthermore, single crystalline diamond nanorods of 4-8 nm in diameter and up to 200 nm in length have been successfully synthesized by hydrogen plasma post

  8. Metal films with imprinted nanostructures by template stripping

    DEFF Research Database (Denmark)

    Eriksen, René Lynge; Pors, Anders; Dreier, Jes

    We present a novel template stripping procedure for fabricating metal films with imprinted nanostructures. The basic idea is to deposit a gold film onto a nano-structured substrate and subsequently strip the film from the substrate surface thereby revealing imprinted nanostructures in the film...... result is a thin gold film with imprinted nano-cavities....

  9. Science and Technology of Nanostructures in the Department of Defense

    International Nuclear Information System (INIS)

    Murday, James S.

    1999-01-01

    The United States Department of Defense maintains a research and development program in nanostructures with special attention to miniaturization of information technology devices, nanostructured materials, and nanobiotechnology for detection of biological agents. This article provides a brief guide to those DoD funding officers and research scientists actively interested in nanostructures

  10. In vitro characterization and in vivo evaluation of nanostructured lipid curcumin carriers for intragastric administration

    Directory of Open Access Journals (Sweden)

    Fang M

    2012-10-01

    Full Text Available Min Fang, Yilin Jin, Wei Bao, Hui Gao, Mengjin Xu, Di Wang, Xia Wang, Ping Yao, Liegang LiuDepartment of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, and Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, People’s Republic of ChinaBackground: Curcumin has a variety of pharmacological effects. However, poor water solubility and low oral bioavailability limit its clinical utility. A delivery system for nanostructured lipid carriers has been reported to be a promising approach to enhancing the oral absorption of curcumin. The aim of the present study was to investigate the pharmacokinetics, tissue distribution, and relative bioavailability of curcumin in rats after a single intragastric dose of a nanostructured lipid curcumin carrier formulation.Methods: Nanostructured lipid curcumin carriers were prepared using the ethanol dripping method and characterized in terms of the particle size, polydispersity index, zeta potential, differential scanning calorimetry, drug-loading capacity, encapsulation efficiency, and in vitro release. The pharmacokinetics and tissue distribution of nanostructured lipid curcumin carriers and curcumin suspension were compared after intragastric administration.Results: Nanostructured lipid curcumin carriers showed a significantly higher peak plasma concentration (564.94 ± 14.98 ng/mL versus 279.43 ± 7.21 ng/mL, P < 0.01, a shorter time taken to reach peak plasma concentration (0.5 ± 0.01 hour versus 1.0 ± 0.12 hour, P < 0.01, and a greater AUC0–∞ (820.36 ± 25.11 mg × hour/L versus 344.11 ± 10.01 mg × hour/L, P < 0.05 compared with curcumin suspension. In the tissue distribution studies, curcumin could be detected in the spleen, heart, liver, kidneys, lungs, and brain. Following intragastric administration of the nanostructured lipid curcumin

  11. Synthesis and processing of nanostructured materials

    International Nuclear Information System (INIS)

    Siegel, R.W.

    1992-12-01

    Significant and growing interest is being exhibited in the novel and enhanced properties of nanostructured materials. These materials, with their constituent phase or grain structures modulated on a length scale less than 100 nm, are artificially synthesized by a wide variety of physical, chemical, and mechanical methods. In this NATO Advanced Study Institute, where mechanical behavior is emphasized, nanostructured materials with modulation dimensionalities from one (multilayers) to three (nanophase materials) are mainly considered. No attempt is made in this review to cover in detail all of the diverse methods available for the synthesis of nanostructured materials. Rather, the basic principles involved in their synthesis are discussed in terms of the special properties sought using examples of particular synthesis and processing methodologies. Some examples of the property changes that can result from one of these methods, cluster assembly of nanophase materials, are presented

  12. Synthesis and AFM visualization of DNA nanostructures

    International Nuclear Information System (INIS)

    Mizuno, Rika; Haruta, Hirotaka; Morii, Takashi; Okada, Takao; Asakawa, Takeshi; Hayashi, Kenshi

    2004-01-01

    We propose a novel bottom-up approach for the fabrication of various desired nanostructures, based on self-assembly of oligonucleotides governed by Watson-Crick base pairing. Using this approach, we designed Y-shaped, closed Y-shaped, H-shaped, and hexagonal structures with oligonucleotides. These structures were autonomously fabricated simply by mixing equimolar solutions of oligonucleotides and performing hybridization. After synthesis of the nanostructures, we confirmed their validity by agarose gel electrophoresis and atomic force microscope (AFM) visualization. We detected bands of the desired molecular sizes in the gel electrophoresis and observed the desired structures by AFM analysis. We concluded that the synthesized structures were consistent with our intended design and that AFM visualization is a very useful tool for the observation of nanostructures

  13. Transport and dynamics of nanostructured graphene

    DEFF Research Database (Denmark)

    Gunst, Tue

    This thesis is concerned with the heating and electronic properties of nanoscale devices based on nanostructured graphene. As electronic devices scale down to nanometer dimensions, the operation depends on the detailed atomic structure. Emerging carbon nano-materials such as graphene, carbon...... nanotubes and graphene nanoribbons, exhibit promising electronic and heat transport properties. Much research addresses the electron mobility of pristine graphene devices. However, the thermal transport properties, as well as the effects of e-ph interaction, in nanoscale devices, based on nanostructured...... graphene, have received much less attention. This thesis contributes to the understanding of the thermal properties of nanostructured graphene. The computational analysis is based on DFT/TB-NEGF. We show how a regular nanoperforation of a graphene layer - a graphene antidot lattice (GAL) - may...

  14. Fractal like charge transport in polyaniline nanostructures

    International Nuclear Information System (INIS)

    Nath, Chandrani; Kumar, A.

    2013-01-01

    The structural and electrical properties of camphorsulfonic acid (CSA) doped nanotubes, and hydrochloric acid (HCl) doped nanofibers and nanoparticles of polyaniline have been studied as a function of doping level. The crystallinity increases with doping for all the nanostructures. Electrical transport measurements in the temperature range of 5–300 K show an increase in conductivity with doping for the nanostructures. All the nanostructures exhibit metal to insulator (MIT) transition below 40 K. The metallic behavior is ascribed to the electron–electron interaction effects. In the insulating regime of the nanotubes conduction follows the Mott quasi-1D variable range hopping model, whereas the conduction in the nanofibers and nanoparticles occur by variable range hopping of charge carriers among superlocalized states without and with Coulomb interaction, respectively. The smaller dopant size in case of HCl makes the polymer fractal resulting in superlocalization of electronic wave-functions. The confined morphology of the nanoparticles results in effective Coulomb interaction dominating the intersite hopping

  15. Electrode Nanostructures in Lithium‐Based Batteries

    Science.gov (United States)

    Mahmood, Nasir

    2014-01-01

    Lithium‐based batteries possessing energy densities much higher than those of the conventional batteries belong to the most promising class of future energy devices. However, there are some fundamental issues related to their electrodes which are big roadblocks in their applications to electric vehicles (EVs). Nanochemistry has advantageous roles to overcome these problems by defining new nanostructures of electrode materials. This review article will highlight the challenges associated with these chemistries both to bring high performance and longevity upon considering the working principles of the various types of lithium‐based (Li‐ion, Li‐air and Li‐S) batteries. Further, the review discusses the advantages and challenges of nanomaterials in nanostructured electrodes of lithium‐based batteries, concerns with lithium metal anode and the recent advancement in electrode nanostructures. PMID:27980896

  16. Metal oxide nanostructures as gas sensing devices

    CERN Document Server

    Eranna, G

    2016-01-01

    Metal Oxide Nanostructures as Gas Sensing Devices explores the development of an integrated micro gas sensor that is based on advanced metal oxide nanostructures and is compatible with modern semiconductor fabrication technology. This sensor can then be used to create a compact, low-power, handheld device for analyzing air ambience. The book first covers current gas sensing tools and discusses the necessity for miniaturized sensors. It then focuses on the materials, devices, and techniques used for gas sensing applications, such as resistance and capacitance variations. The author addresses the issues of sensitivity, concentration, and temperature dependency as well as the response and recovery times crucial for sensors. He also presents techniques for synthesizing different metal oxides, particularly those with nanodimensional structures. The text goes on to highlight the gas sensing properties of many nanostructured metal oxides, from aluminum and cerium to iron and titanium to zinc and zirconium. The final...

  17. Electron Microscopy of Nanostructures in Cells

    DEFF Research Database (Denmark)

    Købler, Carsten

    with cells is therefore increasingly more relevant from both an engineering and a toxicological viewpoint. My work involves developing and exploring electron microscopy (EM) for imaging nanostructures in cells, for the purpose of understanding nanostructure-cell interactions in terms of their possibilities...... in science and concerns in toxicology. In the present work, EM methods for imaging nanostructure-cell interactions have been explored, and the complex interactions documented and ordered. In particular the usability of the focused ion beam scanning electron microscope (FIB-SEM) was explored. Using EM...... in literature. Furthermore, EM proved valuable as it revealed an unnoticed CNT effect. FIB-SEM helped establish that the effect was linked to eosionophilic crystalline pneumonia (ECP)....

  18. Spin currents in metallic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Czeschka, Franz Dominik

    2011-09-05

    A pure spin current, i.e., a flow of angular momentum without accompanying net charge current, is a key ingredient in the field of spintronics. In this thesis, we experimentally investigated two different concepts for pure spin current sources suggested by theory. The first is based on a time-dependent magnetization precession which ''pumps'' a pure spin current into an adjacent non-magnetic conductor. Our experiments quantitatively corroborated important predictions expected theoretically for this approach, including the dependence of the spin current on the sample geometry and the microwave power. Even more important, we could show for the first time that the spin pumping concept is viable in a large variety of ferromagnetic materials and that it only depends on the magnetization damping. Therefore, our experiments established spin pumping as generic phenomenon and demonstrated that it is a powerful way to generate pure spin currents. The second theoretical concept is based on the conversion of charge currents into spin currents in non-magnetic nanostructures via the spin Hall effect. We experimentally investigated this approach in H-shaped, metallic nanodevices, and found that the predictions are linked to requirements not realizable with the present experimental techniques, neither in sample fabrication nor in measurement technique. Indeed, our experimental data could be consistently understood by a spin-independent transport model describing the transition from diffusive to ballistic transport. In addition, the implementation of advanced fabrication and measurement techniques allowed to discover a new non-local phenomenon, the non-local anisotropic magnetoresistance. Finally, we also studied spin-polarized supercurrents carried by spin-triplet Cooper pairs. We found that low resistance interfaces are a key requirement for further experiments in this direction. (orig.)

  19. Optical properties of nitride nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Cantarero, A.; Cros, A.; Garro, N.; Gomez-Gomez, M.I.; Garcia, A.; Lima, M.M. de [Materials Science Institute, University of Valencia, PO Box 22085, 46071 Valencia (Spain); Daudin, B. [Departement de Recherche Fondamentale sur la Matiere Condensee, SPMM, CEA/Grenoble, 17 Rue des Martyrs, 38054 Grenoble (France); Rizzi, A.; Denker, C.; Malindretos, J. [IV. Physikalisches Institut, Georg August Universitaet Goettingen, 37073 Goettingen (Germany)

    2011-01-15

    In this paper we review some recent results on the optical properties of nitride nanostructures, in particular on GaN quantum dots (QDs) and InN nanocolumns (NCs). First, we will give a brief introduction on the particularities of vibrational modes of wurtzite. The GaN QDs, embedded in AlN, were grown by molecular beam epitaxy (MBE) in the Stransky-Krastanov mode on c- and a-plane 6H-SiC. We have studied the optical properties by means of photoluminescence (PL) and performed Raman scattering measurements to analyze the strain relaxation in the dots and the barrier, the effect of the internal electric fields, and the influence of specific growth parameters, like the influence of capping or the spacer on the relaxation of the QDs. A theoretical model, based on continuous elastic theory, were developed to interpret the Raman scattering results. On the other hand, InN NCs have been grown by MBE in the vapor-liquid-solid mode using Au as a catalyst. The nanocolumns have different morphology depending on the growth conditions. The optical properties can be correlated to the morphology of the samples and the best growth conditions can be selected. We observe, from the analysis of the Raman data in InN NCs, the existence of two space regions contributing to the scattering: the surface and the inner region. From the inner region, uncoupled phonon modes are clearly observed, showing the high crystal quality and the complete relaxation of the NCs (no strain). The observation of a LO-phonon-plasmon couple in the same spectra is a fingerprint of the accumulation layer predicted at the surface of the nanocolumns. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Nanostructured Diclofenac Sodium Releasing Material

    Science.gov (United States)

    Nikkola, L.; Vapalahti, K.; Harlin, A.; Seppälä, J.; Ashammakhi, N.

    2008-02-01

    Various techniques have been developed to produce second generation biomaterials for tissue repair. These include extrusion, molding, salt leaching, spinning etc, but success in regenerating tissues has been limited. It is important to develop porous material, yet with a fibrous structure for it to be biomimetic. To mimic biological tissues, the extra-cellular matrix usually contains fibers in nano scale. To produce nanostructures, self-assembly or electrospinning can be used. Adding a drug release function to such a material may advance applications further for use in controlled tissue repair. This turns the resulting device into a multifunctional porous, fibrous structure to support cells and drug releasing properties in order to control tissue reactions. A bioabsorbable poly(ɛ-caprolactone-co-D,L lactide) 95/5 (PCL) was made into diluted solution using a solvent, to which was added 2w-% of diclofenac sodium (DS). Nano-fibers were made by electrospinning onto substrate. Microstructure of the resulting nanomat was studied using SEM and drug release profiles with UV/VIS spectroscopy. Thickness of the electrospun nanomat was about 2 mm. SEM analysis showed that polymeric nano-fibers containing drug particles form a highly interconnected porous nano structure. Average diameter of the nano-fibers was 130 nm. There was a high burst peak in drug release, which decreased to low levels after one day. The used polymer has slow a degradation rate and though the nanomat was highly porous with a large surface area, drug release rate is slow. It is feasible to develop a nano-fibrous porous structure of bioabsorbable polymer, which is loaded with test drug. Drug release is targeted at improving the properties of biomaterial for use in controlled tissue repair and regeneration.

  1. 2009 Clusters, Nanocrystals & Nanostructures GRC

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lai-Sheng [Washington State Univ., Pullman, WA (United States)

    2009-07-19

    For over thirty years, this Gordon Conference has been the premiere meeting for the field of cluster science, which studies the phenomena that arise when matter becomes small. During its history, participants have witnessed the discovery and development of many novel materials, including C60, carbon nanotubes, semiconductor and metal nanocrystals, and nanowires. In addition to addressing fundamental scientific questions related to these materials, the meeting has always included a discussion of their potential applications. Consequently, this conference has played a critical role in the birth and growth of nanoscience and engineering. The goal of the 2009 Gordon Conference is to continue the forward-looking tradition of this meeting and discuss the most recent advances in the field of clusters, nanocrystals, and nanostructures. As in past meetings, this will include new topics that broaden the field. In particular, a special emphasis will be placed on nanomaterials related to the efficient use, generation, or conversion of energy. For example, we anticipate presentations related to batteries, catalysts, photovoltaics, and thermoelectrics. In addition, we expect to address the controversy surrounding carrier multiplication with a session in which recent results addressing this phenomenon will be discussed and debated. The atmosphere of the conference, which emphasizes the presentation of unpublished results and lengthy discussion periods, ensures that attendees will enjoy a valuable and stimulating experience. Because only a limited number of participants are allowed to attend this conference, and oversubscription is anticipated, we encourage all interested researchers from academia, industry, and government institutions to apply as early as possible. An invitation is not required. We also encourage all attendees to submit their latest results for presentation at the poster sessions. We anticipate that several posters will be selected for 'hot topic' oral

  2. Cation-Induced Stabilization and Denaturation of DNA Origami Nanostructures in Urea and Guanidinium Chloride.

    Science.gov (United States)

    Ramakrishnan, Saminathan; Krainer, Georg; Grundmeier, Guido; Schlierf, Michael; Keller, Adrian

    2017-11-01

    The stability of DNA origami nanostructures under various environmental conditions constitutes an important issue in numerous applications, including drug delivery, molecular sensing, and single-molecule biophysics. Here, the effect of Na + and Mg 2+ concentrations on DNA origami stability is investigated in the presence of urea and guanidinium chloride (GdmCl), two strong denaturants commonly employed in protein folding studies. While increasing concentrations of both cations stabilize the DNA origami nanostructures against urea denaturation, they are found to promote DNA origami denaturation by GdmCl. These inverse behaviors are rationalized by a salting-out of Gdm + to the hydrophobic DNA base stack. The effect of cation-induced DNA origami denaturation by GdmCl deserves consideration in the design of single-molecule studies and may potentially be exploited in future applications such as selective denaturation for purification purposes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Polymer Masks for nanostructuring of graphene

    DEFF Research Database (Denmark)

    Shvets, Violetta

    This PhD project is a part of Center for Nanostructured Graphene (CNG) activities. The aim of the project is to develop a new lithography method for creation of highly ordered nanostructures with as small as possible feature and period sizes. The method should be applicable for graphene nanostruc...... demonstrated the opening of what could be interpreted as a band gap....... polymer masks is developed. Mask fabrication is realized by microtoming of 30-60 nm thin sections from pre-aligned polymer monoliths with different morphologies. The resulting polymer masks are then transferred to both silicon and graphene substrates. Hexagonally packed hole patterns with 10 nm hole...

  4. Research of Self-Formation Nanostructures

    Directory of Open Access Journals (Sweden)

    Romas Petrauskas

    2011-08-01

    Full Text Available Lateral etching processes for the modeling of the geometry of self-formation nanostructures with Silvaco TCAD Athena program are analyzed. Self-formation nanostructures is modeled with different mask selectivity values equal to 2, 10, 40 and 100 with respect to the etching layer, with the etching duration of 0–180 s. The etching rates are constant – 1.33 nm/s. The analysis of the dependence of the etching systematic error on its thickness has been carried out. The computer modeled results are close to the ones produced by means of the application of the analytical calculation models by other authors.Article in Lithuanian

  5. Nanowires and nanostructures fabrication using template methods

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.; Vlad, A.

    2009-01-01

    One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis ...... of nanowires and nanostructures using nanoporous host materials such as supported anodic aluminum considering it as a key template for nanowires based devices. New ways are opened for applications by combining such template synthesis methods with nanolithographic techniques....

  6. About possible technologies of creation nanostructures blankets

    International Nuclear Information System (INIS)

    Blednova, Zh.M.; Chaevskij, M.I.; Rusinov, P.O.

    2008-01-01

    Possible technologies of formation nanostructures blankets are considered: a method of thermal carrying over of weights in the conditions of a high gradient of temperatures; the combined method including cathode-plasma nitriding in the conditions of low pressure and drawing of nitride of the titan in a uniform work cycle; the combined method including high-frequency ionic nitriding and drawing of carbide of chrome by pyrolysis chrome and organic of connections in plasma of the decaying category. Possibility of formation layered nanostructures layers is shown.

  7. Nanocoatings size effect in nanostructured films

    CERN Document Server

    Aliofkhazraei, Mahmood

    2014-01-01

    Size effect in structures has been taken into consideration over the last years. In comparison with coatings with micrometer-ranged thickness, nanostructured coatings usually enjoy better and appropriate properties, such as strength and resistance. These coatings enjoy unique magnetic properties and are used with the aim of producing surfaces resistant against erosion, lubricant system, cutting tools, manufacturing hardened sporadic alloys, being resistant against oxidation and corrosion. This book reviews researches on fabrication and classification of nanostructured coatings with focus on size effect in nanometric scale. Size effect on electrochemical, mechanical and physical properties of nanocoatings are presented.

  8. Engineered Metallic Nanostructures: Fabrication, Characterization, and Applications

    Science.gov (United States)

    Bohloul, Arash

    Metallic nanostructures have garnered a great deal of attention due to their fascinating optical properties, which differ from the bulk metal. They have been proven to exceed expectations in wide variety of applications including chemical and biological sensing. Nevertheless, high-throughput and low cost nanofabrication techniques are required to implant metallic nanostructures in widespread applications. With that vision, this thesis presents a versatile and reliable method for scalable fabrication of gold nanostructures. In this approach, a plasma-treated ordered array of polystyrene nanospheres acts as an initial mask. The key step in this process is the vapor-deposition of nickel as a sacrificial mask. Thereby, gold nanostructures are directly formed on the substrate through the nickel mask. This is an easy, powerful, and straightforward method that offers several degrees of freedom to precisely control the shape and size of nanostructures. We made a library of nanostructures including gold nanocrescents, double crescents, nanorings, and nanodisks with the ability to tune the size in the range of 150 to 650 nm. The fabricated nanostructures are highly packed and uniformly cover the centimeter scale substrate. The optical properties of metallic nanostructures were extensively studied by a combination of UV-Vis-NIR and Fourier transform infrared (FTIR) spectroscopies, and correlation between optical response and geometrical parameters were investigated. In the next part of this thesis, highly sensitive surface enhanced infrared absorption (SEIRA) analysis was demonstrated on gold nanocrescent arrays. Theoretical modeling was confirmed that these substrates provide highly dense and strong hot-spots over the substrate, which is required for surface enhanced spectroscopic studies. Gold nanocrescent arrays exhibit highly tunable plasmon resonance to cover desired molecular vibrational bands. These substrates experimentally illustrated 3 orders of magnitude

  9. Plasmon-modulated photoluminescence from gold nanostructures and its dependence on plasmon resonance, excitation energy, and band structure

    NARCIS (Netherlands)

    Le Thi Ngoc, Loan; Wiedemair, Justyna; van den Berg, Albert; Carlen, Edwin

    2015-01-01

    Two distinct single-photon plasmon-modulated photoluminescence processes are generated from nanostructured gold surfaces by tuning the spectral overlap of the incident laser source, localized surface plasmon resonance band, and the interband transitions between the d and sp bands, near the X-and

  10. Crystallization of a self-assembled three-dimensional DNA nanostructure

    International Nuclear Information System (INIS)

    Rendek, Kimberly N.; Fromme, Raimund; Grotjohann, Ingo; Fromme, Petra

    2013-01-01

    In this work, the crystallization of a self-assembling three-dimensional B-DNA nanostructure is described. The powerful and specific molecular-recognition system present in the base-pairing of DNA allows for the design of a plethora of nanostructures. In this work, the crystallization of a self-assembling three-dimensional B-DNA nanostructure is described. The DNA nanostructure consists of six single-stranded oligonucleotides that hybridize to form a three-dimensional tetrahedron of 80 kDa in molecular mass and 20 bp on each edge. Crystals of the tetrahedron have been successfully produced and characterized. These crystals may form the basis for an X-ray structure of the tetrahedron in the future. Nucleotide crystallography poses many challenges, leading to the fact that only 1352 X-ray structures of nucleic acids have been solved compared with more than 80 000 protein structures. In this work, the crystallization optimization for three-dimensional tetrahedra is also described, with the eventual goal of producing nanocrystals to overcome the radiation-damage obstacle by the use of free-electron laser technology in the future

  11. Self-Consolidation Mechanism of Nanostructured Ti5Si3 Compact Induced by Electrical Discharge

    Directory of Open Access Journals (Sweden)

    W. H. Lee

    2015-01-01

    Full Text Available Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

  12. Size-Induced Switching of Nanowire Growth Direction: a New Approach Toward Kinked Nanostructures

    KAUST Repository

    Shen, Youde

    2016-04-26

    Exploring self-assembled nanostructures with controllable architectures has been a central theme in nanoscience and nanotechnology because of the tantalizing perspective of directly integrating such bottom-up nanostructures into functional devices. Here, the growth of kinked single-crystal In2O3 nanostructures consisting of a nanocone base and a nanowire tip with an epitaxial and defect-free transition is demonstrated for the first time. By tailoring the growth conditions, a reliable switching of the growth direction from [111] to [110] or [112] is observed when the Au catalyst nanoparticles at the apexes of the nanocones shrink below ≈100 nm. The natural formation of kinked nanoarchitectures at constant growth pressures is related to the size-dependent free energy that changes for different orientations of the nanowires. The results suggest that the mechanism of forming such kinked nanocone-nanowire nanostructures in well-controlled growth environment may be universal for a wide range of functional materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Two-color beam improvement of the colloidal particle lens array assisted surface nanostructuring

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, Andrei; Bredikhin, Vladimir; Pikulin, Alexander; Ilyakov, Igor; Shishkin, Boris; Akhmedzhanov, Rinat; Bityurin, Nikita, E-mail: bit@ufp.appl.sci-nnov.ru [Institute of Applied Physics of Russian Academy of Scienses, 46, Ul' yanov St., Nizhniy Novgorod 603950 (Russian Federation)

    2015-05-04

    We consider laser nanostructuring of the material surface by means of a colloidal particle lens array. Here, the monolayer of dielectric micro- or nanospheres placed on the surface acts as an array of near-field lenses that focus the laser radiation into the multitude of distinct spots, allowing the formation of many structures in a single stage. We show that conversion of a small part of the energy of the femtosecond beam into the second harmonic (SH) is an efficient way to increase the surface density of obtained nanostructures. By combining the fundamental frequency and the SH, one benefits both from the power of the former and from the focusing ability of the latter. This combination provides an efficient nanostructuring with sphere diameter close to the wavelength of the second harmonic. The possibility to create arrays of nanostructures with surface density above 5×10{sup 8} cm{sup −2} with femtosecond Ti:sapphire laser operating at 800 nm was demonstrated by employing 0.45 μm spheres.

  14. Size-Induced Switching of Nanowire Growth Direction: a New Approach Toward Kinked Nanostructures

    KAUST Repository

    Shen, Youde; Lebedev, Oleg I.; Turner, Stuart; Van Tendeloo, Gustaaf; Song, Xiaohui; Yu, Xuechao; Wang, Qijie; Chen, Hongyu; Dayeh, Shadi A.; Wu, Tao

    2016-01-01

    Exploring self-assembled nanostructures with controllable architectures has been a central theme in nanoscience and nanotechnology because of the tantalizing perspective of directly integrating such bottom-up nanostructures into functional devices. Here, the growth of kinked single-crystal In2O3 nanostructures consisting of a nanocone base and a nanowire tip with an epitaxial and defect-free transition is demonstrated for the first time. By tailoring the growth conditions, a reliable switching of the growth direction from [111] to [110] or [112] is observed when the Au catalyst nanoparticles at the apexes of the nanocones shrink below ≈100 nm. The natural formation of kinked nanoarchitectures at constant growth pressures is related to the size-dependent free energy that changes for different orientations of the nanowires. The results suggest that the mechanism of forming such kinked nanocone-nanowire nanostructures in well-controlled growth environment may be universal for a wide range of functional materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. What makes a feather shine? A nanostructural basis for glossy black colours in feathers.

    Science.gov (United States)

    Maia, Rafael; D'Alba, Liliana; Shawkey, Matthew D

    2011-07-07

    Colours in feathers are produced by pigments or by nanostructurally organized tissues that interact with light. One of the simplest nanostructures is a single layer of keratin overlying a linearly organized layer of melanosomes that create iridescent colours of feather barbules through thin-film interference. Recently, it has been hypothesized that glossy (i.e. high specular reflectance) black feathers may be evolutionarily intermediate between matte black and iridescent feathers, and thus have a smooth keratin layer that produces gloss, but not the layered organization of melanosomes needed for iridescence. However, the morphological bases of glossiness remain unknown. Here, we use a theoretical approach to generate predictions about morphological differences between matte and glossy feathers that we then empirically test. Thin-film models predicted that glossy spectra would result from a keratin layer 110-180 nm thick and a melanin layer greater than 115 nm thick. Transmission electron microscopy data show that nanostructure of glossy barbules falls well within that range, but that of matte barbules does not. Further, glossy barbules had a thinner and more regular keratin cortex, as well as a more continuous underlying melanin layer, than matte barbules. Thus, their quasi-ordered nanostructures are morphologically intermediate between matte black and iridescent feathers, and perceived gloss may be a form of weakly chromatic iridescence.

  16. Nanostructured magnesium oxide biosensing platform for cholera detection

    Science.gov (United States)

    Patel, Manoj K.; Azahar Ali, Md.; Agrawal, Ved V.; Ansari, Z. A.; Ansari, S. G.; Malhotra, B. D.

    2013-04-01

    We report fabrication of highly crystalline nanostructured magnesium oxide (NanoMgO, size >30 nm) film electrophoretically deposited onto indium-tin-oxide (ITO) glass substrate for Vibrio cholerae detection. The single stranded deoxyribonucleic acid (ssDNA) probe, consisting of 23 bases (O1 gene sequence) immobilized onto NanoMgO/ITO electrode surface, has been characterized using electrochemical, Fourier Transform-Infra Red, and UltraViolet-visible spectroscopic techniques. The hybridization studies of ssDNA/NanoMgO/ITO bioelectrode with fragmented target DNA conducted using differential pulse voltammetry reveal sensitivity as 16.80 nA/ng/cm2, response time of 3 s, linearity as 100-500 ng/μL, and stability of about 120 days.

  17. Ballistic transport through graphene nanostructures of velocity and potential barriers

    International Nuclear Information System (INIS)

    Krstajic, P M; Vasilopoulos, P

    2011-01-01

    We investigate the electronic properties of graphene nanostructures when the Fermi velocity and the electrostatic potential vary in space. First, we consider the transmission T and conductance G through single and double barriers. We show that G for velocity barriers differs markedly from that for potential barriers for energies below the height of the latter and it exhibits periodic oscillations as a function of the energy for strong velocity modulation. Special attention is given to superlattices (SLs). It is shown that an applied bias can efficiently widen or shrink the allowed minibands of velocity-modulated SLs. The spectrum in the Kronig-Penney limit is periodic in the strength of the barriers. Collimation of an electron beam incident on an SL with velocity and potential barriers is present but it disappears when the potential barriers are absent. The number of additional Dirac points may change considerably if barriers and wells have sufficiently different Fermi velocities.

  18. Nanostructuring superconductors by ion beams: A path towards materials engineering

    Energy Technology Data Exchange (ETDEWEB)

    Gerbaldo, Roberto; Ghigo, Gianluca; Gozzelino, Laura; Laviano, Francesco [Department of Applied Science and Technology, Politecnico di Torino c.so Duca degli Abruzzi 24, 10129 Torino, Italy and INFN Sez. Torino, via P. Giuria 1, 10125 Torino (Italy); Amato, Antonino; Rovelli, Alberto [INFN Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Cherubini, Roberto [INFN Laboratori Nazionali di Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy)

    2013-07-18

    The paper deals with nanostructuring of superconducting materials by means of swift heavy ion beams. The aim is to modify their structural, optical and electromagnetic properties in a controlled way, to provide possibility of making them functional for specific applications. Results are presented concerning flux pinning effects (implantation of columnar defects with nanosize cross section to enhance critical currents and irreversibility fields), confined flux-flow and vortex guidance, design of devices by locally tailoring the superconducting material properties, analysis of disorder-induced effects in multi-band superconductors. These studies were carried out on different kinds of superconducting samples, from single crystals to thin films, from superconducting oxides to magnesium diboride, to recently discovered iron-based superconductors.

  19. Mechanical Researches on Young's Modulus of SCS Nanostructures

    Directory of Open Access Journals (Sweden)

    Qinhua Jin

    2009-01-01

    Full Text Available Nanostructures of SingleCrystalSilicon (SCS with superior electrical, mechanical, thermal, and optical properties are emerging in the development of novel nanodevices. Mechanical properties especially Young's modulus are essential in developing and utilizing such nanodevices. In this paper, experimental researches including bending tests, resonance tests, and tensile tests on Young' s modulus of nanoscaled SCS are reviewed, and their results are compared. It was found that the values of E measured by different testing methods cannot match to each other. As the differences cannot be explained as experimental errors, it should be understood by taking surface effect into account. With a simplified model, we qualitatively explained the difference in E value measured by tensile test and by resonance test for Si nanobeams.

  20. Topography and refractometry of nanostructures using spatial light interference microscopy.

    Science.gov (United States)

    Wang, Zhuo; Chun, Ik Su; Li, Xiuling; Ong, Zhun-Yong; Pop, Eric; Millet, Larry; Gillette, Martha; Popescu, Gabriel

    2010-01-15

    Spatial light interference microscopy (SLIM) is a novel method developed in our laboratory that provides quantitative phase images of transparent structures with a 0.3 nm spatial and 0.03 nm temporal accuracy owing to the white light illumination and its common path interferometric geometry. We exploit these features and demonstrate SLIM's ability to perform topography at a single atomic layer in graphene. Further, using a decoupling procedure that we developed for cylindrical structures, we extract the axially averaged refractive index of semiconductor nanotubes and a neurite of a live hippocampal neuron in culture. We believe that this study will set the basis for novel high-throughput topography and refractometry of man-made and biological nanostructures.

  1. Programmable molecular recognition based on the geometry of DNA nanostructures.

    Science.gov (United States)

    Woo, Sungwook; Rothemund, Paul W K

    2011-07-10

    From ligand-receptor binding to DNA hybridization, molecular recognition plays a central role in biology. Over the past several decades, chemists have successfully reproduced the exquisite specificity of biomolecular interactions. However, engineering multiple specific interactions in synthetic systems remains difficult. DNA retains its position as the best medium with which to create orthogonal, isoenergetic interactions, based on the complementarity of Watson-Crick binding. Here we show that DNA can be used to create diverse bonds using an entirely different principle: the geometric arrangement of blunt-end stacking interactions. We show that both binary codes and shape complementarity can serve as a basis for such stacking bonds, and explore their specificity, thermodynamics and binding rules. Orthogonal stacking bonds were used to connect five distinct DNA origami. This work, which demonstrates how a single attractive interaction can be developed to create diverse bonds, may guide strategies for molecular recognition in systems beyond DNA nanostructures.

  2. Apodized grating coupler using fully-etched nanostructures

    International Nuclear Information System (INIS)

    Wu Hua; Li Chong; Guo Xia; Li Zhi-Yong

    2016-01-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. (paper)

  3. New Computational Approach to Electron Transport in Irregular Graphene Nanostructures

    Science.gov (United States)

    Mason, Douglas; Heller, Eric; Prendergast, David; Neaton, Jeffrey

    2009-03-01

    For novel graphene devices of nanoscale-to-macroscopic scale, many aspects of their transport properties are not easily understood due to difficulties in fabricating devices with regular edges. Here we develop a framework to efficiently calculate and potentially screen electronic transport properties of arbitrary nanoscale graphene device structures. A generalization of the established recursive Green's function method is presented, providing access to arbitrary device and lead geometries with substantial computer-time savings. Using single-orbital nearest-neighbor tight-binding models and the Green's function-Landauer scattering formalism, we will explore the transmission function of irregular two-dimensional graphene-based nanostructures with arbitrary lead orientation. Prepared by LBNL under contract DE-AC02-05CH11231 and supported by the U.S. Dept. of Energy Computer Science Graduate Fellowship under grant DE-FG02-97ER25308.

  4. Critical sizes and critical characteristics of nanoclusters, nanostructures and nanomaterials

    International Nuclear Information System (INIS)

    Suzdalev, I.P.

    2005-01-01

    Full text: Critical sizes and characteristics of nanoclusters and nanostructures are introduced as the parameters of nanosystems and nanomaterials. The next critical characteristics are considered: atomic and electronic 'magic number', critical size of cluster nucleation, critical size of melting-freezing of cluster, critical size of quantum (laser) radiation, critical sizes for the single electron conductivity, critical energy and magnetic field for the magnetic tunneling, critical cluster sizes for the giant magnetic resistance, critical size of the first order magnetic phase transition. The critical characteristics are estimated by thermodynamic approaches, by Moessbauer spectroscopy, AFM, heat capacity, SQUID magnetometry and other technique, The influence of cluster-cluster interactions, cluster-matrix interactions and cluster defects on cluster atomic dynamics, cluster melting, cluster critical sizes, Curie or Neel points and the character of magnetic phase transitions were investigated. The applications of critical size and critical characteristic parameters for the nanomaterial characterization are considered

  5. Polarization dependent nanostructuring of silicon with femtosecond vortex pulse

    Directory of Open Access Journals (Sweden)

    M. G. Rahimian

    2017-08-01

    Full Text Available We fabricated conical nanostructures on silicon with a tip dimension of ∼ 70 nm using a single twisted femtosecond light pulse carrying orbital angular momentum (ℓ=±1. The height of the nano-cone, encircled by a smooth rim, increased from ∼ 350 nm to ∼ 1 μm with the pulse energy and number of pulses, whereas the apex angle remained constant. The nano-cone height was independent of the helicity of the twisted light; however, it is reduced for linear polarization compared to circular at higher pulse energies. Fluid dynamics simulations show nano-cones formation when compressive forces arising from the radial inward motion of the molten material push it perpendicular to the surface and undergo re-solidification. Simultaneously, the radial outward motion of the molten material re-solidifies after reaching the cold boundary to form a rim. Overlapping of two irradiated spots conforms to the fluid dynamics model.

  6. Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

    Science.gov (United States)

    Guo, Junpeng (Inventor)

    2016-01-01

    The present disclosure pertains to metal or dielectric nanostructures of the subwavelength scale within the grating lines of optical diffraction gratings. The nanostructures have surface plasmon resonances or non-plasmon optical resonances. A linear photodetector array is used to capture the resonance spectra from one of the diffraction orders. The combined nanostructure super-grating and photodetector array eliminates the use of external optical spectrometers for measuring surface plasmon or optical resonance frequency shift caused by the presence of chemical and biological agents. The nanostructure super-gratings can be used for building integrated surface enhanced Raman scattering (SERS) spectrometers. The nanostructures within the diffraction grating lines enhance Raman scattering signal light while the diffraction grating pattern of the nanostructures diffracts Raman scattering light to different directions of propagation according to their wavelengths. Therefore, the nanostructure super-gratings allows for the use of a photodetector array to capture the surface enhanced Raman scattering spectra.

  7. Magnetic properties of nickel nanostructures grown in AAO membrane

    International Nuclear Information System (INIS)

    Oh, S.-L.; Kim, Y.-R.; Malkinski, L.; Vovk, A.; Whittenburg, S.L.; Kim, E.-M.; Jung, J.-S.

    2007-01-01

    One-dimensional nanostructures can be built by performing chemical or electrochemical reactions in the pores of a suitable host or matrix material. We have developed a method of electrodeposition of nickel nanostructures inside cylindrical pores of the anodic aluminum oxide (AAO) membranes, which provides precise control of the nanostructure height. We were able to fabricate hexagonal arrays of particles in the form of spheres, rods and long wires. Magnetization measurements of these nanostructures as function of field and temperature were carried out using a superconducting quantum-interference device magnetometer. The shape of nickel nanostructures has been investigated by field emission scanning electron microscope. The coercivity of the nickel nanostructures measured with the field perpendicular to the membrane was increasing with increasing aspect ratio of the nanostructures. These experimental values of the coercivity, varying from 200 Oe for the spherical nanodots to 730 Oe for the nanowires, are in a fair agreement with our micromagnetic modeling calculations

  8. Magnetic properties of nickel nanostructures grown in AAO membrane

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S -L [Department of Chemistry, Yonsei University, Seoul (Korea, Republic of); Kim, Y -R [Department of Chemistry, Yonsei University, Seoul (Korea, Republic of); Malkinski, L [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Vovk, A [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Whittenburg, S L [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Kim, E -M [Korea Basic Science Institute, Kangnung 210-702 (Korea, Republic of); Jung, J -S [Department of Chemistry, Kangnung National University, Kangnung 210-702 (Korea, Republic of)

    2007-03-15

    One-dimensional nanostructures can be built by performing chemical or electrochemical reactions in the pores of a suitable host or matrix material. We have developed a method of electrodeposition of nickel nanostructures inside cylindrical pores of the anodic aluminum oxide (AAO) membranes, which provides precise control of the nanostructure height. We were able to fabricate hexagonal arrays of particles in the form of spheres, rods and long wires. Magnetization measurements of these nanostructures as function of field and temperature were carried out using a superconducting quantum-interference device magnetometer. The shape of nickel nanostructures has been investigated by field emission scanning electron microscope. The coercivity of the nickel nanostructures measured with the field perpendicular to the membrane was increasing with increasing aspect ratio of the nanostructures. These experimental values of the coercivity, varying from 200 Oe for the spherical nanodots to 730 Oe for the nanowires, are in a fair agreement with our micromagnetic modeling calculations.

  9. On the Adsorption of DNA Origami Nanostructures in Nanohole Arrays.

    Science.gov (United States)

    Brassat, Katharina; Ramakrishnan, Saminathan; Bürger, Julius; Hanke, Marcel; Doostdar, Mahnaz; Lindner, Jörg K N; Grundmeier, Guido; Keller, Adrian

    2018-05-22

    DNA origami nanostructures are versatile substrates for the controlled arrangement of molecular capture sites with nanometer precision and thus have many promising applications in single-molecule bioanalysis. Here, we investigate the adsorption of DNA origami nanostructures in nanohole arrays which represent an important class of biosensors and may benefit from the incorporation of DNA origami-based molecular probes. Nanoholes with well-defined diameter that enable the adsorption of single DNA origami triangles are fabricated in Au films on Si wafers by nanosphere lithography. The efficiency of directed DNA origami adsorption on the exposed SiO 2 areas at the bottoms of the nanoholes is evaluated in dependence of various parameters, i.e., Mg 2+ and DNA origami concentrations, buffer strength, adsorption time, and nanohole diameter. We observe that the buffer strength has a surprisingly strong effect on DNA origami adsorption in the nanoholes and that multiple DNA origami triangles with 120 nm edge length can adsorb in nanoholes as small as 120 nm in diameter. We attribute the latter observation to the low lateral mobility of once adsorbed DNA origami on the SiO 2 surface, in combination with parasitic adsorption to the Au film. Although parasitic adsorption can be suppressed by modifying the Au film with a hydrophobic self-assembled monolayer, the limited surface mobility of the adsorbed DNA origami still leads to poor localization accuracy in the nanoholes and results in many DNA origami crossing the boundary to the Au film even under optimized conditions. We discuss possible ways to minimize this effect by varying the composition of the adsorption buffer, employing different fabrication conditions, or using other substrate materials for nanohole array fabrication.

  10. Monodisperse Multidimensional Nanostructures via Centrifugal Separation

    Science.gov (United States)

    Shin, Yu Jin

    Anisotropic nanomaterials, including zero-dimensional metallic nanoparticles (MNPs), one-dimensional single-walled carbon nanotubes (SWCNTs), and two-dimensional few-layer black phosphorous (FL-P) exhibit interesting structure-dependent properties that could be exploited in biomedicine, plasmonics, and optoelectronics. In this thesis, centrifugation sorting of these nanomaterials is utilized for structure refinement, investigation of structure-dependent optical response, and applications in biomedical imaging and plasmonics. Nobel NMPs show unique shape- and size-dependent optical properties. Controlled synthetic methods are developed to manipulate the structure of these NMPs, but intrinsically produce dispersions of polydisperse NPs with various shape and size, and synthetic byproducts. Here, we describe a facile strategy for separating small (edge length 80%) and subsequently achieve a 2.5 fold enhancement in refractive index sensitivity, comparable to the unsorted mixture. This shallow DGC approach is robust and reliable, and therefore can be applied to other metal nanostructures for concomitant improvements in plasmonic properties and applications. Using the identical separation strategy in the previous study, we are able to enrich gold nanostars as a function of branch number. In particular, we explore different variants of density gradient media to ensure compatibility with the star shape and colloid stability. We determine that sucrose is compatible with nanostars stability and surface functionalizaton. The refined population of gold stars are functionalized with Gd(III)-DNA to act as MRI contrast agents, and thus enables us to investigate how populations of nanostars with different branch numbers contribute to the relaxivity of surface bound Gd(III)-DNA. It is shown that the increased relaxivity of DNA-Gd star is correlated with increased number of star branches, not with increased size of the stars. Therefore, shape is a new parameter which can be tuned in

  11. Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

    Science.gov (United States)

    Shi, Weidong; Song, Shuyan; Zhang, Hongjie

    2013-07-07

    Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

  12. Fullerenes and nanostructured plastic solar cells

    NARCIS (Netherlands)

    Knol, Joop; Hummelen, Jan C.; Kuzmany, H; Fink, J; Mehring, M; Roth, S

    1998-01-01

    We report on the present on the present status of the plastic solar cell and on the design of fullerene derivatives and pi-conjugated donor molecules that can function as acceptor-donor pairs and (supra-) molecular building blocks in organized, nanostructured interpenetrating networks, forming a

  13. Electroluminescence from Silicon and Germanium Nanostructures ...

    African Journals Online (AJOL)

    The EL and PL intensities occurs at the same energy; however, the EL intensity has sharp Gaussian sub peaks and red shifted compared to the PL intensity. To get our result, we used the idea of quantum confinement model (QCM), that can explain PL and EL on pure Si nanostructures and Si-terminated with impurities.

  14. 3D Printed Block Copolymer Nanostructures

    Science.gov (United States)

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  15. Nanostructure-initiator mass spectrometry biometrics

    Science.gov (United States)

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  16. Functional nanostructures on injection molded plastic

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Søgaard, Emil; Andersen, Nis Korsgaard

    Nanotechnology can be used to make inexpensive plastic parts with functional surfaces. The plastic parts can be molded using a standard injection molding process. The nanostructures are directly transferred from the surface of the molding tool to the surface of the molded plastic part during...

  17. Ballistic transport in semiconductor nanostructures: From quasi ...

    Indian Academy of Sciences (India)

    By suitable design it is possible to achieve quasi-ballistic transport in semiconductor nanostructures over times up to the ps-range. Monte-Carlo simulations reveal that under these conditions phase-coherent real-space oscillations of an electron ensemble, generated by fs-pulses become possible in wide potential wells.

  18. Microwave dielectric properties of nanostructured nickel ferrite

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Nickel ferrite is one of the important ferrites used in microwave devices. In the present work, we have synthesized nanoparticles of nickel ferrite using chemical precipitation technique. The crystal structure and grain size of the particles are studied using XRD. The microwave dielectric properties of nanostructured.

  19. Numerical simulations of nanostructured gold films

    DEFF Research Database (Denmark)

    Repän, Taavi; Frydendahl, Christian; Novikov, Sergey M.

    2017-01-01

    We present an approach to analyse near-field effects on nanostructured gold films by finite element simulations. The studied samples are formed by fabricating gold films near the percolation threshold and then applying laser damage. Resulting samples have complicated structures, which...

  20. Controlling light with resonant plasmonic nanostructures

    NARCIS (Netherlands)

    Waele, R. de

    2009-01-01

    Plasmons are collective oscillations of free electrons in a metal. At optical frequencies plasmons enable nanoscale confinement of light in metal nanostructures. This ability has given rise to many applications in e.g. photothermal cancer treatment, light trapping in photovoltaic cells, and sensing.

  1. Synthesis of vertically aligned metal oxide nanostructures

    KAUST Repository

    Roqan, Iman S.; Flemban, Tahani H.

    2016-01-01

    ablation of a target including a metal oxide and, optionally, a dopant. In some embodiments zinc oxide nanostructures are deposited onto a substrate by pulsed laser deposition of a zinc oxide target using an excimer laser emitting UV radiation. The zinc

  2. Injection Molding of High Aspect Ratio Nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels Bent

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters...

  3. Monocrystalline halide perovskite nanostructures for optoelectronic applications

    NARCIS (Netherlands)

    Khoram, P.

    2018-01-01

    Halide perovskites are a promising class of materials for incorporation in optoelectronics with higher efficiency and lower cost. The solution processability of these materials provides unique opportunities for simple nanostructure fabrication. In the first half of the thesis (chapter 2 and 3) we

  4. Willmore energy for joining of carbon nanostructures

    Science.gov (United States)

    Sripaturad, P.; Alshammari, N. A.; Thamwattana, N.; McCoy, J. A.; Baowan, D.

    2018-06-01

    Numerous types of carbon nanostructure have been found experimentally, including nanotubes, fullerenes and nanocones. These structures have applications in various nanoscale devices and the joining of these structures may lead to further new configurations with more remarkable properties and applications. The join profile between different carbon nanostructures in a symmetric configuration may be modelled using the calculus of variations. In previous studies, carbon nanostructures were assumed to deform according to perfect elasticity, thus the elastic energy, depending only on the axial curvature, was used to determine the join profile consisting of a finite number of discrete bonds. However, one could argue that the relevant energy should also involve the rotational curvature, especially when its size is comparable to the axial curvature. In this paper, we use the Willmore energy, a natural generalisation of the elastic energy that depends on both the axial and rotational curvatures. Catenoids are absolute minimisers of this energy and pieces of these may be used to join various nanostructures. We focus on the cases of joining a fullerene to a nanotube and joining two fullerenes along a common axis. By comparing our results with the earlier work, we find that both energies give similar joining profiles. Further work on other configurations may reveal which energy provides a better model.

  5. Synthesis of In2O3 nanostructures with different morphologies as potential supercapacitor electrode materials

    Science.gov (United States)

    Tuzluca, Fatma Nur; Yesilbag, Yasar Ozkan; Ertugrul, Mehmet

    2018-01-01

    In this study performed using a chemical vapor deposition (CVD) system, one-dimensional (1-D) single crystal indium oxide (In2O3) nanotowers, nanobouqets, nanocones, and nanowires were investigated as a candidate for a supercapacitor electrode material. These nanostructures were grown via Vapor-Liquid-Solid (VLS) and Vapor-Solid (VS) mechanisms according to temperature differences (1000-600 °C). The morphologies, growth mechanisms and crystal structures of these 1-D single crystal In2O3 nanostructures were defined by Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HR-TEM), X-Ray Diffraction (XRD) and Raman Spectroscopy analyses. The elemental analyses of the nanostructures were carried out by energy dispersive X-Ray Spectroscopy (EDS); they gave photoluminescence (PL) spectra with 3.39, 2.65, and 1.95 eV band gap values, corresponding to 365 nm, 467 nm, and 633 wavelengths, respectively. The electrochemical performances of these 1-D single crystal In2O3 nanostructures in an aqueous electrolyte solution (1 M Na2SO4) were determined by Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) analyses. According to GCD measurements at 0.04 mA cm-2 current density, areal capacitance values were 10.1 mF cm-2 and 6.7 mF cm-2 for nanotowers, 12.5 mF cm-2 for nanobouquets, 4.9 mF cm-2 for nanocones, and 16.6 mF cm-2 for nanowires. The highest areal capacitance value was observed in In2O3 nanowires, which retained 66.8% of their initial areal capacitance after a 10000 charge-discharge cycle, indicating excellent cycle stability.

  6. ROS mediated malignancy cure performance of morphological, optical, and electrically tuned Sn doped CeO2 nanostructures

    Science.gov (United States)

    Abbas, Fazal; Iqbal, Javed; Maqbool, Qaisar; Jan, Tariq; Ullah, Muhammad Obaid; Nawaz, Bushra; Nazar, Mudassar; Naqvi, M. S. Hussain; Ahmad, Ishaq

    2017-09-01

    To grapple with cancer, implementation of differentially cytotoxic nanomedicines have gained prime attention of the researchers across the globe. Now, ceria (CeO2) at nanoscale has emerged as a cut out therapeutic agent for malignancy treatment. Keeping this in view, we have fabricated SnxCe1-xO2 nanostructures by facile, eco-friendly, and biocompatible hydrothermal method. Structural examinations via XRD and FT-IR spectroscopy have revealed single phase cubic-fluorite morphology while SEM analysis has depicted particle size ranging 30-50nm for pristine and doped nanostructures. UV-Vis spectroscopy investigation explored that Sn doping significantly tuned the band gap (eV) energies of SnxCe1-xO2 nanostructures which set up the base for tremendous cellular reactive oxygen species (ROS) generations involved in cancer cells' death. To observe cytotoxicity, synthesized nanostructures were found selectively more toxic to neuroblastoma cell lines as compared to HEK-293 healthy cells. This study anticipates that SnxCe1-xO2 nanostructures, in future, might be used as nanomedicine for safer cancer therapy.

  7. ROS mediated malignancy cure performance of morphological, optical, and electrically tuned Sn doped CeO2 nanostructures

    Directory of Open Access Journals (Sweden)

    Fazal Abbas

    2017-09-01

    Full Text Available To grapple with cancer, implementation of differentially cytotoxic nanomedicines have gained prime attention of the researchers across the globe. Now, ceria (CeO2 at nanoscale has emerged as a cut out therapeutic agent for malignancy treatment. Keeping this in view, we have fabricated SnxCe1-xO2 nanostructures by facile, eco-friendly, and biocompatible hydrothermal method. Structural examinations via XRD and FT-IR spectroscopy have revealed single phase cubic-fluorite morphology while SEM analysis has depicted particle size ranging 30-50nm for pristine and doped nanostructures. UV-Vis spectroscopy investigation explored that Sn doping significantly tuned the band gap (eV energies of SnxCe1-xO2 nanostructures which set up the base for tremendous cellular reactive oxygen species (ROS generations involved in cancer cells’ death. To observe cytotoxicity, synthesized nanostructures were found selectively more toxic to neuroblastoma cell lines as compared to HEK-293 healthy cells. This study anticipates that SnxCe1-xO2 nanostructures, in future, might be used as nanomedicine for safer cancer therapy.

  8. The in vitro sub-cellular localization and in vivo efficacy of novel chitosan/GMO nanostructures containing paclitaxel.

    Science.gov (United States)

    Trickler, W J; Nagvekar, A A; Dash, A K

    2009-08-01

    To determine the in vitro sub-cellular localization and in vivo efficacy of chitosan/GMO nanostructures containing paclitaxel (PTX) compared to a conventional PTX treatment (Taxol). The sub-cellular localization of coumarin-6 labeled chitosan/GMO nanostructures was determined by confocal microscopy in MDA-MB-231 cells. The antitumor efficacy was evaluated in two separate studies using FOX-Chase (CB17) SCID Female-Mice MDA-MB-231 xenograph model. Treatments consisted of intravenous Taxol or chitosan/GMO nanostructures with or without PTX, local intra-tumor bolus of Taxol or chitosan/GMO nanostructures with or without PTX. The tumor diameter and animal weight was monitored at various intervals. Histopathological changes were evaluated in end-point tumors. The tumor diameter increased at a constant rate for all the groups between days 7-14. After a single intratumoral bolus dose of chitosan/GMO containing PTX showed significant reduction in tumor diameter on day 15 when compared to control, placebo and intravenous PTX administration. The tumor diameter reached a maximal decrease (4-fold) by day 18, and the difference was reduced to approximately 2-fold by day 21. Qualitatively similar results were observed in a separate study containing PTX when administered intravenously. Chitosan/GMO nanostructures containing PTX are safe and effective administered locally or intravenously. Partially supported by DOD Award BC045664.

  9. Nanostructured Tip-Shaped Biosensors: Application of Six Sigma Approach for Enhanced Manufacturing.

    Science.gov (United States)

    Kahng, Seong-Joong; Kim, Jong-Hoon; Chung, Jae-Hyun

    2016-12-23

    Nanostructured tip-shaped biosensors have drawn attention for biomolecule detection as they are promising for highly sensitive and specific detection of a target analyte. Using a nanostructured tip, the sensitivity is increased to identify individual molecules because of the high aspect ratio structure. Various detection methods, such as electrochemistry, fluorescence microcopy, and Raman spectroscopy, have been attempted to enhance the sensitivity and the specificity. Due to the confined path of electrons, electrochemical measurement using a nanotip enables the detection of single molecules. When an electric field is combined with capillary action and fluid flow, target molecules can be effectively concentrated onto a nanotip surface for detection. To enhance the concentration efficacy, a dendritic nanotip rather than a single tip could be used to detect target analytes, such as nanoparticles, cells, and DNA. However, reproducible fabrication with relation to specific detection remains a challenge due to the instability of a manufacturing method, resulting in inconsistent shape. In this paper, nanostructured biosensors are reviewed with our experimental results using dendritic nanotips for sequence specific detection of DNA. By the aid of the Six Sigma approach, the fabrication yield of dendritic nanotips increases from 20.0% to 86.6%. Using the nanotips, DNA is concentrated and detected in a sequence specific way with the detection limit equivalent to 1000 CFU/mL. The pros and cons of a nanotip biosensor are evaluated in conjunction with future prospects.

  10. Mn-based nanostructured building blocks: Synthesis, characterization and applications

    Science.gov (United States)

    Beltran Huarac, Juan

    -up approaches towards the fabrication of different types of functional MBNs. Likewise, strategic procedures that advance the facile integration of these self-assembled nanostructures with carbon-based and magnetic/optical materials, chalcogenides, oxides, and ferroics are widely analyzed and discussed. Furthermore, we present the attractive peculiarities of three versatile MBN systems (bridging the gap between their advantageous properties and the lack of methods for their fabrication): single-crystal saw-like MnS NRs, and single-crystal MnS NWs conformally coated with carbon; doped rare-earth manganite NCs, and carbon NTs conformally coated with doped rare-earth manganite; and ZnS:Mn NPs, and Fe3O4/ZnS:Mn NCs. Concerning the applicative significance, the main features of these three systems obtained by our method are suitable to advance direct applications in nanotechnology. In this regard, this work represents a step ahead in the following areas: i) alternative anode materials to enhance the capacity and cycling performance of low-drain, long-life, low-cost, high-energy density light-weight and safer lithium-ion batteries; ii) promising luminescent materials to improve the optoelectronic performance of visible light emitters; iii) new elements for field-effect transistors that outperform the transport properties of conventional carbon-based channels; iv) bifunctional materials exhibiting optical response sensitive to external magnetic fields vital for DMS; v) novel types of nanocantilevers useful for nanosensors and nanotweezers; vi) unique multiferroics materials that exhibit magnetoelectric coupling at room temperature for spintronics; vii) potential core-shell materials showing stress-free and protective carbon shells for shock-resistance semiconductors; and viii) high-quality ceramics useful as starting materials to deposit films by pulsed laser deposition, sputtering and thermal evaporation techniques.

  11. Topotactic reduction yielding black titanium oxide nanostructures as metallic electronic conductors.

    Science.gov (United States)

    Tominaka, Satoshi

    2012-10-01

    Detailed analyses of reduced, single crystal, rutile-type TiO(2) via high-resolution transmission electron microscopy (TEM) are reported which reveal that the reduction proceeds topotactically via interstitial diffusion of Ti ions at low temperature, around 350 °C. This important finding encouraged the production of various nanostructured reduced titanium oxides from TiO(2) precursors with morphology retention, and in the process, the synthesis of black titanium oxide nanorods using TiO(2) nanorods was demonstrated. Interestingly, as opposed to the semiconductive behavior of Ti(2)O(3) synthesized at high temperature, topotactically synthesized Ti(2)O(3) exhibits metallic electrical resistance, and the value at room temperature is quite low (topotactically synthesized Ti(2)O(3). This work shows that topotactically reduced titanium oxides can have fascinating properties as well as nanostructures.

  12. Anion Exchange in II-VI Semiconducting Nanostructures via Atomic Templating.

    Science.gov (United States)

    Agarwal, Rahul; Krook, Nadia M; Ren, Ming-Liang; Tan, Liang Z; Liu, Wenjing; Rappe, Andrew M; Agarwal, Ritesh

    2018-03-14

    Controlled chemical transformation of nanostructures is a promising technique to obtain precisely designed novel materials, which are difficult to synthesize otherwise. We report high-temperature vapor-phase anion-exchange reactions to chemically transform II-VI semiconductor nanostructures (100-300 nm length scale) while retaining the single crystallinity, crystal structure, morphology, and even defect distribution of the parent material via atomic templating. The concept of atomic templating is employed to obtain kinetically controlled, thermodynamically metastable structural phases such as zincblende CdSe and CdS from zincblende CdTe upon complete chemical replacement of Te with Se or S. The underlying transformation mechanisms are explained through first-principles density functional theory calculations. Atomic templating is a unique path to independently tune materials' phase and composition at the nanoscale, allowing the synthesis of novel materials.

  13. Design, Fabrication, and Characterization of Hematite (α-Fe2O3) Nanostructures

    Science.gov (United States)

    Jansi Rani, B.; Mageswari, R.; Ravi, G.; Ganesh, V.; Yuvakkumar, R.

    2017-12-01

    The influence of processing parameters on the physicochemical properties of hematite α-Fe2O3 nanostructures was investigated. X-ray diffraction results revealed the hematite phase rhombohedral structure. Scanning electron microscope results explored nanospheres, nanohexagonal platelets, nanoellipsoids, distorted nanocubes, and interconnected platelets nanostructures. Rhombohedral single-phase hematite was confirmed through five Raman active modes. 2 P 3/2 (1) → 2 P 1/2 transition in photoluminescence spectra and Fourier-transform infrared spectroscopy band observed at 555 cm-1 revealed the hematite formation. The highest specific capacitance value of 151.09 F/g for scan rate of 10 mV/s was obtained for the hydrothermal-assisted product using an Fe(NO3)2·9H2O precursor in KOH electrolyte solutions.

  14. Spectroscopic investigations of nanostructured LiNbO3 doped with Eu3+

    International Nuclear Information System (INIS)

    Hreniak, D.; Speghini, A.; Bettinelli, M.; Strek, W.

    2006-01-01

    Structural and optical properties of the sol-gel derived nanocrystalline lithium niobate (LiNbO 3 ) powders doped with Eu 3+ ions have been studied. In particular, the influence of the sizes of nanoparticles controlled by temperature on the structural and luminescence properties has been investigated. Emission bands corresponding to 5 D emission became more resolved with increasing nanocrystal size and changed to a typical Eu 3+ :LiNbO 3 single crystal spectrum for nanocrystals having an average size of more than 40 nm. Nonlinear optical properties of nanostructured LiNbO 3 have been confirmed by simple observation of second harmonic generation effect (SHG). The possibility of using nanostructured LiNbO 3 doped with rare-earth ions as self-doubling elements in integrated optoelectronic devices has been discussed

  15. In Vivo Deep Tissue Fluorescence and Magnetic Imaging Employing Hybrid Nanostructures.

    Science.gov (United States)

    Ortgies, Dirk H; de la Cueva, Leonor; Del Rosal, Blanca; Sanz-Rodríguez, Francisco; Fernández, Nuria; Iglesias-de la Cruz, M Carmen; Salas, Gorka; Cabrera, David; Teran, Francisco J; Jaque, Daniel; Martín Rodríguez, Emma

    2016-01-20

    Breakthroughs in nanotechnology have made it possible to integrate different nanoparticles in one single hybrid nanostructure (HNS), constituting multifunctional nanosized sensors, carriers, and probes with great potential in the life sciences. In addition, such nanostructures could also offer therapeutic capabilities to achieve a wider variety of multifunctionalities. In this work, the encapsulation of both magnetic and infrared emitting nanoparticles into a polymeric matrix leads to a magnetic-fluorescent HNS with multimodal magnetic-fluorescent imaging abilities. The magnetic-fluorescent HNS are capable of simultaneous magnetic resonance imaging and deep tissue infrared fluorescence imaging, overcoming the tissue penetration limits of classical visible-light based optical imaging as reported here in living mice. Additionally, their applicability for magnetic heating in potential hyperthermia treatments is assessed.

  16. Characterization of ZnO nanostructures: A challenge to positron annihilation spectroscopy and other methods

    Energy Technology Data Exchange (ETDEWEB)

    Brauer, Gerhard; Anwand, Wolfgang; Grambole, Dieter; Skorupa, Wolfgang [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden-Rossendorf, Dresden (Germany); Egger, Werner; Sperr, Peter [Institut fuer Angewandte Physik und Messtechnik LRT2, Fakultaet fuer Luft- und Raumfahrttechnik, Werner-Heisenberg-Weg 39, Universitaet der Bundeswehr, Neubiberg (Germany); Beinik, Igor; Wang, Lin; Teichert, Christian [Institut fuer Physik, Montanuniversitaet Leoben (Austria); Kuriplach, Jan; Lang, Jan [Department of Low Temperature Physics, Charles University, Prague (Czech Republic); Zviagin, Sergei; Cizmar, Erik [Institut Hochfeld-Magnetlabor, Forschungszentrum Dresden-Rossendorf, Dresden (Germany); Ling, Chi Chung; Hsu, Yuk Fan; Xi, Yan Yan; Chen, Xinyi; Djurisic, Aleksandra B. [Department of Physics, University of Hong Kong, Hong Kong (China)

    2009-11-15

    ZnO nanostructures are of special interest for device applications. However, their structural characterization remains an ongoing challenge. This paper reviews recent efforts and latest achievements in this direction. Results comprise PAS in the form of Slow Positron Implantation Spectroscopy (SPIS) and Pulsed Low Energy Positron Lifetime Spectroscopy (PLEPS), Nuclear Reaction Analysis (NRA), Atomic Force Microscopy (AFM), conductive AFM (C-AFM), Nuclear Magnetic Resonance (NMR), Electron Spin Resonance (ESR), Photoluminescence (PL) spectroscopy, and latest theoretical investigations of structure-related and positron properties of selected defects. The fundamental importance of a relationship between fabrication conditions, native defect formation, and resulting optical and electronic properties is demonstrated by getting either inferior (nanorods) or significantly improved (tetrapods) optical properties compared to single crystal samples, depending on the nanostructure fabrication method. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Optical properties of hybrid quantum-well–dots nanostructures grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Mintairov, S. A., E-mail: mintairov@scell.ioffe.ru; Kalyuzhnyy, N. A.; Nadtochiy, A. M.; Maximov, M. V. [St. Petersburg Academic University (Russian Federation); Rouvimov, S. S. [University of Notre Dame (United States); Zhukov, A. E. [St. Petersburg Academic University (Russian Federation)

    2017-03-15

    The deposition of In{sub x}Ga{sub 1–x}As with an indium content of 0.3–0.5 and an average thickness of 3–27 single layers on a GaAs wafer by metalorganic chemical vapor deposition (MOCVD) at low temperatures results in the appearance of thickness and composition modulations in the layers being formed. Such structures can be considered to be intermediate nanostructures between ideal quantum wells and quantum dots. Depending on the average thickness and composition of the layers, the wavelength of the photoluminescence peak for the hybrid InGaAs quantum well–dots nanostructures varies from 950 to 1100 nm. The optimal average In{sub x}Ga{sub 1–x}As thicknesses and compositions at which the emission wavelength is the longest with a high quantum efficiency retained are determined.

  18. InTaO4-based nanostructures synthesized by reactive pulsed laser ablation

    International Nuclear Information System (INIS)

    Yoshida, Takehito; Toyoyama, Hirokazu; Umezu, Ikurou; Sugimura, Akira

    2008-01-01

    Nanostructured Ni-doped indium-tantalum-oxides (InTaO 4 ) were synthesized by a reactive pulsed laser ablation process, aiming at the final goal of direct splitting of water under visible sunbeam irradiation. The third harmonics beam of a Nd:YAG laser was focused onto a sintered In 0.9 Ni 0.1 TaO 4-δ target in pure oxygen background gases (0.05-1.00 Torr). Increasing the oxygen gas pressure, via thin films having nanometer-sized strong morphologies, single-crystalline nanoparticles were synthesized in the reactive vapor phases. The nanostructured deposited materials have the monoclinic layered wolframite-type structure of bulk InTaO 4 , without oxygen deficiency. (orig.)

  19. Nanostructured silicon nitride from wheat and rice husks

    Energy Technology Data Exchange (ETDEWEB)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R. [Materials Science and Component Technology Directorate, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2016-04-07

    Nanoparticles, submicron-diameter tubes, and rods of Si{sub 3}N{sub 4} were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si{sub 3}N{sub 4} with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si{sub 3}N{sub 4}. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si{sub 3}N{sub 4} combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  20. Electrochemical synthesis of magnetic nanostructures using anodic aluminum oxide templates

    Science.gov (United States)

    Gong, Jie

    In this dissertation, template electrodeposition was employed to fabricate high quality magnetic nanostructures suited for the reliable investigation of novel spintronics phenomena such as CIMS, BMR, and CPP-GMR. Several critical aspects/steps relating to the synthesis process were investigated in this work. In order to obtain high quality magnetic nanostructures, free-standing and Si-supported anodic aluminum oxide templates with closely controlled pore diameters, lengths, as well as constriction sizes, were synthesized by anodization, followed by appropriate post-processing. The pore opening size on the barrier layer can be controlled down to 5 nm by ion beam etching. After optimization of the compositional, structural, and magnetic properties of homogeneous FeCoNiCu layers electrodeposited under different conditions, the pulsed deposition process of FeCoNI/Cu multilayers on n-Si was studied. The influence of Cu deposition potential and Fe2+ concentration on microstructure, chemical and electrochemical properties, magnetic properties, and hence magnetotransport properties were assessed. The dissolution of the FM layer during potential transition was minimized in order to control interface sharpness. Combined with the systematic sublayer thickness and FM layer composition optimization, unprecedented GMR sensitivity of 0.11%/Oe at 5-15 Oe was obtained. Growth of multilayer nanowires was performed, and contact to a single wire was attempted using an electrochemical technique. We succeeded in addressing a small number of nanowires and measured a CPP-GMR of 17%. Template electrodeposition thus provides a promising way to repeatably fabricate prototypes for spin dependent transport studies.

  1. Development of a gold-nanostructured surface for amperometric genosensors

    Energy Technology Data Exchange (ETDEWEB)

    Zanardi, Chiara, E-mail: chiara.zanardi@unimore.it [Universita di Modena e Reggio Emilia, Dipartimento di Chimica (Italy); Baldoli, Clara, E-mail: clara.baldoli@istm.cnr.it [Istituto di Scienze e Tecnologie Molecolari del CNR (Italy); Licandro, Emanuela [Universita degli Studi di Milano, Dipartimento di Chimica Organica ed Industriale (Italy); Terzi, Fabio; Seeber, Renato [Universita di Modena e Reggio Emilia, Dipartimento di Chimica (Italy)

    2012-10-15

    A gold-nanostructured surface has been obtained by stable deposition of chemically synthesized gold nanoparticles (2.1-5.5 nm size range) on a gold substrate through a dithiol linker. The method proposed for the obtainment of the nanostructure is suitable for the further stable anchoring of a peptide nucleic acid oligomer through four amine groups of lysine terminal residues, leading to fairly reproducible systems. The geometric area of the nanostructured surface is compared with those of a smooth and of an electrochemically generated nanostructured surface by depositing a probe bearing an electrochemically active ferrocene residue. Despite the area of the two nanostructures being quite similar, the response toward a 2 nM target oligonucleotide sequence is particularly high when using the surface built up by nanoparticle deposition. This aspect indicates that morphologic details of the nanostructure play a key role in conditioning the performances of the genosensors.

  2. Development of a gold-nanostructured surface for amperometric genosensors

    International Nuclear Information System (INIS)

    Zanardi, Chiara; Baldoli, Clara; Licandro, Emanuela; Terzi, Fabio; Seeber, Renato

    2012-01-01

    A gold-nanostructured surface has been obtained by stable deposition of chemically synthesized gold nanoparticles (2.1–5.5 nm size range) on a gold substrate through a dithiol linker. The method proposed for the obtainment of the nanostructure is suitable for the further stable anchoring of a peptide nucleic acid oligomer through four amine groups of lysine terminal residues, leading to fairly reproducible systems. The geometric area of the nanostructured surface is compared with those of a smooth and of an electrochemically generated nanostructured surface by depositing a probe bearing an electrochemically active ferrocene residue. Despite the area of the two nanostructures being quite similar, the response toward a 2 nM target oligonucleotide sequence is particularly high when using the surface built up by nanoparticle deposition. This aspect indicates that morphologic details of the nanostructure play a key role in conditioning the performances of the genosensors.

  3. Selective Oxidations using Nanostructured Heterogeneous Catalysts

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen

    and because they produce H2O as the only by-product. Chapter 1 gives a short introduction to basic concepts in heterogeneous catalysis and green chemistry. Furthermore, the chapter gives an overview of the most important strategies to synthesise functional nanostructured materials and highlights how detailed......The aim of this thesis is to investigate and develop new efficient methods to oxidise alcohols and amines using heterogeneous catalysts and either O2 or H2O2 as oxidants. From an economic and environmental point of view, these oxidants are ideal, because they are cheap and readily available...... understanding of size, shape and structure can help in the development of new and more efficient heterogeneous catalysts. The chapter is not intended to give a complete survey, but rather to introduce some of the recent developments in the synthesis of nanostructured heterogeneous catalysts. Finally...

  4. Forging Colloidal Nanostructures via Cation Exchange Reactions.

    Science.gov (United States)

    De Trizio, Luca; Manna, Liberato

    2016-09-28

    Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field.

  5. semiconducting nanostructures: morphology and thermoelectric properties

    Science.gov (United States)

    Culebras, Mario; Torán, Raquel; Gómez, Clara M.; Cantarero, Andrés

    2014-08-01

    Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1- x Ca x MnO 3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

  6. Engineering Metal Nanostructure for SERS Application

    Directory of Open Access Journals (Sweden)

    Yanqin Cao

    2013-01-01

    Full Text Available Surface-enhanced Raman scattering (SERS has attracted great attention due to its remarkable enhancement and excellent selectivity in the detection of various molecules. Noble metal nanomaterials have usually been employed for producing substrates that can be used in SERS because of their unique local plasma resonance. As the SERS enhancement of signals depends on parameters such as size, shape, morphology, arrangement, and dielectric environment of the nanostructure, there have been a number of studies on tunable nanofabrication and synthesis of noble metals. In this work, we will illustrate progress in engineering metallic nanostructures with various morphologies using versatile methods. We also discuss their SERS applications in different fields and the challenges.

  7. Leafy nanostructure PANI for material of supercapacitors

    Directory of Open Access Journals (Sweden)

    XI Dong

    2013-06-01

    Full Text Available Nanostructure conducting polyaniline(PANI has great potential applications in supercapacitor electrode materials.In this paper,we report a template-free approach to synthesize PANI by a galvanostatic current procedure with a three-electrode configuration directly on indium-doped tin-oxide substrates (ITO.The morphology of product was characterized by Hitachi S-4800 field emission scanning electron microscope (FE-SEM.Due to the nanostructure,the specific capacitance of PANI film with the thickness of 100nm were measured as high as 829 F/g and 667 F/g at a charge-discharge current density of 1 A/g and 10 A/g respectively.After 500 cycle charge-discharge test employed at the current density of 20 A/g the PANI film still had a 95.1% capacitance retention.

  8. Pbte Nanostructures for Spin Filtering and Detecting

    Science.gov (United States)

    Grabecki, G.

    2005-08-01

    An uniqueness of lead telluride PbTe relies on combination of excellent semiconducting properties, like high electron mobility and tunable carrier concentration, with paraelectric behavior leading to huge dielectric constant at low temperatures. The present article is a review of our experimental works performed on PbTe nanostructures. The main result is observation of one-dimensional quantization of the electron motion at much impure conditions than in any other system studied so far. We explain this in terms of dielectric screening of Coulomb potentials produced by charged defects. Furthermore, in an external magnetic field, the conductance quantization steps show very pronounced spin splitting, already visible at several kilogauss. This indicates that PbTe nanostructures have a potential as local spin filtering devices.

  9. Nanostructured metal foams: synthesis and applications

    Energy Technology Data Exchange (ETDEWEB)

    Luther, Erik P [Los Alamos National Laboratory; Tappan, Bryce [Los Alamos National Laboratory; Mueller, Alex [Los Alamos National Laboratory; Mihaila, Bogdan [Los Alamos National Laboratory; Volz, Heather [Los Alamos National Laboratory; Cardenas, Andreas [Los Alamos National Laboratory; Papin, Pallas [Los Alamos National Laboratory; Veauthier, Jackie [Los Alamos National Laboratory; Stan, Marius [Los Alamos National Laboratory

    2009-01-01

    Fabrication of monolithic metallic nanoporous materials is difficult using conventional methodology. Here they report a relatively simple method of synthesizing monolithic, ultralow density, nanostructured metal foams utilizing self-propagating combustion synthesis of novel metal complexes containing high nitrogen energetic ligands. Nanostructured metal foams are formed in a post flame-front dynamic assembly with densities as low as 0.011 g/cc and surface areas as high as 270 m{sup 2}/g. They have produced metal foams via this method of titanium, iron, cobalt, nickel, zirconium, copper, palladium, silver, hafnium, platinum and gold. Microstructural features vary as a function of composition and process parameters. Applications for the metal foams are discussed including hydrogen absorption in palladium foams. A model for the sorption kinetics of hydrogen in the foams is presented.

  10. Nanostructured electrocatalysts with tunable activity and selectivity

    Science.gov (United States)

    Mistry, Hemma; Varela, Ana Sofia; Kühl, Stefanie; Strasser, Peter; Cuenya, Beatriz Roldan

    2016-04-01

    The field of electrocatalysis has undergone tremendous advancement in the past few decades, in part owing to improvements in catalyst design at the nanoscale. These developments have been crucial for the realization of and improvement in alternative energy technologies based on electrochemical reactions such as fuel cells. Through the development of novel synthesis methods, characterization techniques and theoretical methods, rationally designed nanoscale electrocatalysts with tunable activity and selectivity have been achieved. This Review explores how nanostructures can be used to control electrochemical reactivity, focusing on three model reactions: O2 electroreduction, CO2 electroreduction and ethanol electrooxidation. The mechanisms behind nanoscale control of reactivity are discussed, such as the presence of low-coordinated sites or facets, strain, ligand effects and bifunctional effects in multimetallic materials. In particular, studies of how particle size, shape and composition in nanostructures can be used to tune reactivity are highlighted.

  11. Forging Colloidal Nanostructures via Cation Exchange Reactions

    Science.gov (United States)

    2016-01-01

    Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field. PMID:26891471

  12. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  13. Biomolecule-based nanomaterials and nanostructures.

    Science.gov (United States)

    Willner, Itamar; Willner, Bilha

    2010-10-13

    Biomolecule-nanoparticle (or carbon nanotube) hybrid systems provide new materials that combine the unique optical, electronic, or catalytic properties of the nanoelements with the recognition or biocatalytic functions of biomolecules. This article summarizes recent applications of biomolecule-nanoparticle (or carbon nanotubes) hybrid systems for sensing, synthesis of nanostructures, and for the fabrication of nanoscale devices. The use of metallic nanoparticles for the electrical contacting of redox enzymes with electrodes, and as catalytic labels for the development of electrochemical biosensors is discussed. Similarly, biomolecule-quantum dot hybrid systems are implemented for optical biosensing, and for monitoring intracellular metabolic processes. Also, the self-assembly of biomolecule-metal nanoparticle hybrids into nanostructures and functional nanodevices is presented. The future perspectives of the field are addressed by discussing future challenges and highlighting different potential applications.

  14. Skyrmion states in thin confined polygonal nanostructures

    Science.gov (United States)

    Pepper, Ryan Alexander; Beg, Marijan; Cortés-Ortuño, David; Kluyver, Thomas; Bisotti, Marc-Antonio; Carey, Rebecca; Vousden, Mark; Albert, Maximilian; Wang, Weiwei; Hovorka, Ondrej; Fangohr, Hans

    2018-03-01

    Recent studies have demonstrated that skyrmionic states can be the ground state in thin-film FeGe disk nanostructures in the absence of a stabilising applied magnetic field. In this work, we advance this understanding by investigating to what extent this stabilisation of skyrmionic structures through confinement exists in geometries that do not match the cylindrical symmetry of the skyrmion—such as squares and triangles. Using simulation, we show that skyrmionic states can form the ground state for a range of system sizes in both triangular and square-shaped FeGe nanostructures of 10 nm thickness in the absence of an applied field. We further provide data to assist in the experimental verification of our prediction; to imitate an experiment where the system is saturated with a strong applied field before the field is removed, we compute the time evolution and show the final equilibrium configuration of magnetization fields, starting from a uniform alignment.

  15. AMINO ACIDS APPLICATION TO CREATE OF NANOSTRUCTURES

    Directory of Open Access Journals (Sweden)

    I. S. Chekman

    2014-12-01

    Full Text Available Review is devoted to the amino acids that could be used for nanostructures creation. The investigation of corresponding properties of amino acids is essential for their role definition in creation of nanomedicines. However, amino acid studying as components of nanostructures is insufficient. Study of nanoparticles for medicines creation was initiated by the development of nanotechnology. Amino acids in complexes with the nanoparticles of organic and inorganic nature play an important role for medicines targeting in pathological process. They could reduce toxicity of the nanomaterials used in nanomedicine and are used for creation of biosensors, lab-on-chip and therefore they are a promising material for synthesis of new nanodrugs and diagnostic tools.

  16. TEM of nanostructured metals and alloys

    International Nuclear Information System (INIS)

    Karnthaler, H.P.; Waitz, T.; Rentenberger, C.; Mingler, B.

    2004-01-01

    Nanostructuring has been used to improve the mechanical properties of bulk metals and alloys. Transmission electron microscopy (TEM) including atomic resolution is therefore appropriate to study these nanostructures; four examples are given as follows. (1) The early stages of precipitation at RT were investigated in an Al-Mg-Si alloy. By high resolution TEM it is shown that the precipitates lie on (0 0 1) planes having an ordered structure. (2) In Co alloys the fronts of martensitic phase transformations were analysed showing that the transformation strains are very small thus causing no surface relief. (3) Re-ordering and recrystallization were studied by in situ TEM of an Ni 3 Al alloy being nanocrystalline after severe plastic deformation. (4) In NiTi severe plastic deformation is leading to the formation of amorphous shear bands. From the TEM analysis it is concluded that the amorphization is caused by plastic shear instability starting in the shear bands

  17. Mechanics of Nanostructures: Methods and Results

    Science.gov (United States)

    Ruoff, Rod

    2003-03-01

    We continue to develop and use new tools to measure the mechanics and electromechanics of nanostructures. Here we discuss: (a) methods for making nanoclamps and the resulting: nanoclamp geometry, chemical composition and type of chemical bonding, and nanoclamp strength (effectiveness as a nanoclamp for the mechanics measurements to be made); (b) mechanics of carbon nanocoils. We have received carbon nanocoils from colleagues in Japan [1], measured their spring constants, and have observed extensions exceeding 100% relative to the unloaded length, using our scanning electron microscope nanomanipulator tool; (c) several new devices that are essentially MEMS-based, that allow for improved measurements of the mechanics of psuedo-1D and planar nanostructures. [1] Zhang M., Nakayama Y., Pan L., Japanese J. Appl. Phys. 39, L1242-L1244 (2000).

  18. Structure and conductivity of nanostructured YBCO ceramics

    Science.gov (United States)

    Palchayev, D. K.; Gadzhimagomedov, S. Kh; Murlieva, Zh Kh; Rabadanov, M. Kh; Emirov, R. M.

    2017-12-01

    Superconducting nanostructured ceramics based on YBa2Cu3O7-δ were made of nanopowder obtained by burning nitrate-organic precursors. The structure, morphology, electrical resistivity, and density of ceramics were studied. Various porosity values of the ceramics were achieved by preliminary heat treatment of the nanopowder. The features of conductivity and the reason for increase of the of the superconducting transition temperature in these materials are discussed.

  19. Storage of hydrogen in nanostructured carbon materials

    OpenAIRE

    Yürüm, Yuda; Yurum, Yuda; Taralp, Alpay; Veziroğlu, T. Nejat; Veziroglu, T. Nejat

    2009-01-01

    Recent developments focusing on novel hydrogen storage media have helped to benchmark nanostructured carbon materials as one of the ongoing strategic research areas in science and technology. In particular, certain microporous carbon powders, carbon nanomaterials, and specifically carbon nanotubes stand to deliver unparalleled performance as the next generation of base materials for storing hydrogen. Accordingly, the main goal of this report is to overview the challenges, distinguishing trait...

  20. Nanostructured energy devices equilibrium concepts and kinetics

    CERN Document Server

    Bisquert, Juan

    2014-01-01

    Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu

  1. Nanostructures for all-polymer microfluidic systems

    DEFF Research Database (Denmark)

    Matschuk, Maria; Bruus, Henrik; Larsen, Niels Bent

    2010-01-01

    antistiction coating was found to improve the replication fidelity (shape and depth) of nanoscale features substantially. Arrays of holes of 50 nm diameter/35 nm depth and 100 nm/100 nm diameter, respectively, were mass-produced in cyclic olefin copolymer (Topas 5013) by injection molding. Polymer microfluidic...... channel chip parts resulted from a separate injection molding process. The microfluidic chip part and the nanostructured chip part were successfully bonded to form a sealed microfluidic system using air plasma assisted thermal bonding....

  2. Heat Generation by Irradiated Complex Composite Nanostructures

    DEFF Research Database (Denmark)

    Ma, Haiyan; Tian, Pengfei; Pello, Josselin

    2014-01-01

    Heating of irradiated metallic e-beam generated nanostructures was quantified through direct measurements paralleled by novel model-based numerical calculations. By comparing discs, triangles, and stars we showed how particle shape and composition determines the heating. Importantly, our results...... revealed that substantial heat is generated in the titanium adhesive layer between gold and glass. Even when the Ti layer is as thin as 2 nm it absorbs as much as a 30 nm Au layer and hence should not be ignored....

  3. Airborne Nanostructured Particles and Occupational Health

    Science.gov (United States)

    Maynard, Andrew D.; Kuempel, Eileen D.

    2005-12-01

    Nanotechnology is leading to the development in many field, of new materials and devices in many fields that demonstrate nanostructure-dependent properties. However, concern has been expressed that these same properties may present unique challenges to addressing potential health impact. Airborne particles associated with engineered nanomaterials are of particular concern, as they can readily enter the body through inhalation. Research into the potential occupational health risks associated with inhaling engineered nanostructured particles is just beginning. However, there is a large body of data on occupational and environmental aerosols, which is applicable to developing an initial assessment of potential risk and risk reduction strategies. Epidemiological and pathological studies of occupational and environmental exposures to airborne particles and fibers provide information on the aerosol-related lung diseases and conditions that have been observed in humans. Toxicological studies provide information on the specific disease mechanisms, dose-response relationships, and the particle characteristics that influence toxicity, including the size, surface area, chemistry or reactivity, solubility, and shape. Potential health risk will depend on the magnitude and nature of exposures to airborne nanostructured particles, and on the release, dispersion, transformation and control of materials in the workplace. Aerosol control methods have not been well-characterized for nanometer diameter particles, although theory and limited experimental data indicate that conventional ventilation, engineering control and filtration approaches should be applicable in many situations. Current information supports the development of preliminary guiding principles on working with engineered nanomaterials. However critical research questions remain to be answered before the potential health risk of airborne nanostructured particles in the workplace can be fully addressed.

  4. Imaging magnetic domains in Ni nanostructures

    International Nuclear Information System (INIS)

    Asenjo, A.; Jaafar, M.; Gonzalez, E.M.; Martin, J.I.; Vazquez, M.; Vicent, J.L.

    2007-01-01

    The study of nanomagnets is the subject of increasing scientific effort. The size, the thickness and the geometric shape of the elements determine the magnetic properties and then the domain configuration. In this work, we fabricated by electron-beam lithography the three different arrays of Ni nanostructures keeping the size, the thickness and also the distance constant between the elements but varying the geometry: square, triangular and circular. The domain structure of the nanomagnets is studied by magnetic force microscopy

  5. Modeling the mechanical properties of DNA nanostructures.

    Science.gov (United States)

    Arbona, Jean Michel; Aimé, Jean-Pierre; Elezgaray, Juan

    2012-11-01

    We discuss generalizations of a previously published coarse-grained description [Mergell et al., Phys. Rev. E 68, 021911 (2003)] of double stranded DNA (dsDNA). The model is defined at the base-pair level and includes the electrostatic repulsion between neighbor helices. We show that the model reproduces mechanical and elastic properties of several DNA nanostructures (DNA origamis). We also show that electrostatic interactions are necessary to reproduce atomic force microscopy measurements on planar DNA origamis.

  6. Electron microscopy of nanostructured semiconductor materials

    International Nuclear Information System (INIS)

    Neumann, Wolfgang

    2003-01-01

    For various material systems of low dimensions, including multilayers, islands, and quantum dots, the potential applicability of transmission electron microscopy (TEM) is demonstrated. Conventional TEM is applied to elucidate size, shape, and arrangement of nanostructures, whereas high-resolution imaging is used for visualizing their atomic structure. In addition, microchemical peculiarities of the nanoscopic objects are investigated by analytical TEM techniques (energy-filtered TEM, energy-dispersive X-ray spectroscopy)

  7. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  8. Nanostructured complexes of polyelectrolytes and charged polypeptides

    Czech Academy of Sciences Publication Activity Database

    Müller, M.; Ouyang, W.; Bohatá, Karolína; Kessler, B.

    2010-01-01

    Roč. 12, Sp. Iss. 9 (2010), B519-B528 ISSN 1438-1656. [Sino-German Symposium on Advanced Biomedical Nanostructures /1./. Jena, 26.10.2009-30.10.2009] Institutional research plan: CEZ:AV0Z40500505 Keywords : situ ATR-FTIR * alpha-helical polypeptides * multilayer films Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.746, year: 2010

  9. The Physics and Applications of a 3D Plasmonic Nanostructure

    Science.gov (United States)

    Terranova, Brandon B.

    In this work, the dynamics of electromagnetic field interactions with free electrons in a 3D metallic nanostructure is evaluated theoretically. This dissertation starts by reviewing the relevant fundamentals of plasmonics and modern applications of plasmonic systems. Then, motivated by the need to have a simpler way of understanding the surface charge dynamics on complex plasmonic nanostructures, a new plasmon hybridization tree method is introduced. This method provides the plasmonicist with an intuitive way to determine the response of free electrons to incident light in complex nanostructures within the electrostatic regime. Next, a novel 3D plasmonic nanostructure utilizing reflective plasmonic coupling is designed to perform biosensing and plasmonic tweezing applications. By applying analytical and numerical methods, the effectiveness of this nanostructure at performing these applications is determined from the plasmonic response of the nanostructure to an excitation beam of coherent light. During this analysis, it was discovered that under certain conditions, this 3D nanostructure exhibits a plasmonic Fano resonance resulting from the interference of an in-plane dark mode and an out-of-plane bright mode. In evaluating this nanostructure for sensing changes in the local dielectric environment, a figure of merit of 68 is calculated, which is competitive with current localized surface plasmon resonance refractometric sensors. By evaluating the Maxwell stress tensor on a test particle in the vicinity of the nanostructure, it was found that under the right conditions, this plasmonic nanostructure design is capable of imparting forces greater than 10.5 nN on dielectric objects of nanoscale dimensions. The results obtained in these studies provides new routes to the design and engineering of 3D plasmonic nanostructures and Fano resonances in these systems. In addition, the nanostructure presented in this work and the design principles it utilizes have shown

  10. Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes

    OpenAIRE

    Maijenburg, A.W.

    2014-01-01

    This thesis is entitled “Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes”. Templated electrodeposition is the synthesis technique that was used throughout this thesis, and it comprises the use of a template with specific shape and dimensions for the formation of different types of nanostructures. Throughout this thesis, three different nanostructures were made: nanowires (Chapters 2 to 6), nanotubes (Chapters 2 and 5) and nanocubes (Chapters 7 and ...

  11. Fabrication of Nanostructures Using Self-Assembled Peptides as Templates

    DEFF Research Database (Denmark)

    Castillo, Jaime

    2015-01-01

    the advantages of diphenylalanine are explained step by step offering new alternatives to fabricate nanostructures in a simple and rapid way. The chapter is complemented with techniques to manipulate the self-assembled diphenylalanine nanostructures without changing its properties during the manipulation process.......This chapter evaluates the use of a short-aromatic dipeptide, diphenylalanine, as a template in the fabrication of new nanostructures (nanowires, coaxial nanocables, nanochannels) using materials such as silicon, conducting and non-conducting polymers. Diphenylalanine self...

  12. Nanostructured silver sulfide: synthesis of various forms and their application

    Science.gov (United States)

    Sadovnikov, S. I.; Rempel, A. A.; Gusev, A. I.

    2018-04-01

    The results of experimental studies on nanostructured silver sulfide are analyzed and generalized. The influence of small particle size on nonstoichiometry of silver sulfide is discussed. Methods for the synthesis of various forms of nanostructured Ag2S including nanopowders, stable colloidal solutions, quantum dots, core–shell nanoparticles and heteronanostructures are described. The advantages and drawbacks of different synthetic procedures are analyzed. Main fields of application of nanostructured silver sulfide are considered. The bibliography includes 184 references.

  13. Precipitate strengthening of nanostructured aluminium alloy.

    Science.gov (United States)

    Wawer, Kinga; Lewandowska, Malgorzata; Kurzydlowski, Krzysztof J

    2012-11-01

    Grain boundaries and precipitates are the major microstructural features influencing the mechanical properties of metals and alloys. Refinement of the grain size to the nanometre scale brings about a significant increase in the mechanical strength of the materials because of the increased number of grain boundaries which act as obstacles to sliding dislocations. A similar effect is obtained if nanoscale precipitates are uniformly distributed in coarse grained matrix. The development of nanograin sized alloys raises the important question of whether or not these two mechanisms are "additive" and precipitate strengthening is effective in nanostructured materials. In the reported work, hydrostatic extrusion (HE) was used to obtain nanostructured 7475 aluminium alloy. Nanosized precipitates were obtained by post-HE annealing. It was found that such annealing at the low temperatures (100 degrees C) results in a significant increase in the microhardness (HV0.2) and strength of the nanostructured 7475 aluminium alloy. These results are discussed in terms of the interplay between the precipitation and deformation of nanocrystalline metals.

  14. Tracing Tellurium and Its Nanostructures in Biology.

    Science.gov (United States)

    Zare, Bijan; Nami, Mohammad; Shahverdi, Ahmad-Reza

    2017-12-01

    Tellurium (Te) is a semimetal rare element in nature. Together with oxygen, sulfur (S), and selenium (Se), Te is considered a member of chalcogen group. Over recent decades, Te applications continued to emerge in different fields including metallurgy, glass industry, electronics, and applied chemical industries. Along these lines, Te has recently attracted research attention in various fields. Though Te exists in biologic organisms such as microbes, yeast, and human body, its importance and role and some of its potential implications have long been ignored. Some promising applications of Te using its inorganic and organic derivatives including novel Te nanostructures are being introduced. Before discovery and straightforward availability of antibiotics, Te had considered and had been used as an antibacterial element. Antilishmaniasis, antiinflammatory, antiatherosclerotic, and immuno-modulating properties of Te have been described for many years, while the innovative applications of Te have started to emerge along with nanotechnological advances over the recent years. Te quantum dots (QDs) and related nanostructures have proposed novel applications in the biological detection systems such as biosensors. In addition, Te nanostructures are used in labeling, imaging, and targeted drug delivery systems and are tested for antibacterial or antifungal properties. In addition, Te nanoparticles show novel lipid-lowering, antioxidant, and free radical scavenging properties. This review presents an overview on the novel forms of Te, their potential applications, as well as related toxicity profiles.

  15. Nanostructured metal sulfides for energy storage

    Science.gov (United States)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-08-01

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  16. Metamorphic quantum dots: Quite different nanostructures

    International Nuclear Information System (INIS)

    Seravalli, L.; Frigeri, P.; Nasi, L.; Trevisi, G.; Bocchi, C.

    2010-01-01

    In this work, we present a study of InAs quantum dots deposited on InGaAs metamorphic buffers by molecular beam epitaxy. By comparing morphological, structural, and optical properties of such nanostructures with those of InAs/GaAs quantum dot ones, we were able to evidence characteristics that are typical of metamorphic InAs/InGaAs structures. The more relevant are: the cross-hatched InGaAs surface overgrown by dots, the change in critical coverages for island nucleation and ripening, the nucleation of new defects in the capping layers, and the redshift in the emission energy. The discussion on experimental results allowed us to conclude that metamorphic InAs/InGaAs quantum dots are rather different nanostructures, where attention must be put to some issues not present in InAs/GaAs structures, namely, buffer-related defects, surface morphology, different dislocation mobility, and stacking fault energies. On the other hand, we show that metamorphic quantum dot nanostructures can provide new possibilities of tailoring various properties, such as dot positioning and emission energy, that could be very useful for innovative dot-based devices.

  17. Nanostructured gold microelectrodes for SERS and EIS measurements by incorporating ZnO nanorod growth with electroplating

    Science.gov (United States)

    Zong, Xianli; Zhu, Rong; Guo, Xiaoliang

    2015-01-01

    In this paper, a fine gold nanostructure synthesized on selective planar microelectrodes in micro-chip is realized by using an advanced hybrid fabrication approach incorporating growth of nanorods (NRs) with gold electroplating. By this developed nanostructure, integration of in-situ surface-enhanced Raman spectroscopy (SERS) detection with electrochemical impedance spectroscopy (EIS) measurement for label-free, nondestructive, real-time and rapid monitoring on a single cell has been achieved. Moreover, parameters of Au nanostructures such as size of nanoholes/nanogaps can be controllably adjusted in the fabrication. We have demonstrated a SERS enhancement factor of up to ~2.24 × 106 and double-layer impedance decrease ratio of 90% ~ 95% at low frequency range below 200 kHz by using nanostructured microelectrodes. SERS detection and in-situ EIS measurement of a trapped single cell by using planar microelectrodes are realized to demonstrate the compatibility, multi-functions, high-sensitivity and simplicity of the micro-chip system. This dual function platform integrating SERS and EIS is of great significance in biological, biochemical and biomedical applications. PMID:26558325

  18. Temperature-feedback direct laser reshaping of silicon nanostructures

    Science.gov (United States)

    Aouassa, M.; Mitsai, E.; Syubaev, S.; Pavlov, D.; Zhizhchenko, A.; Jadli, I.; Hassayoun, L.; Zograf, G.; Makarov, S.; Kuchmizhak, A.

    2017-12-01

    Direct laser reshaping of nanostructures is a cost-effective and fast approach to create or tune various designs for nanophotonics. However, the narrow range of required laser parameters along with the lack of in-situ temperature control during the nanostructure reshaping process limits its reproducibility and performance. Here, we present an approach for direct laser nanostructure reshaping with simultaneous temperature control. We employ thermally sensitive Raman spectroscopy during local laser melting of silicon pillar arrays prepared by self-assembly microsphere lithography. Our approach allows establishing the reshaping threshold of an individual nanostructure, resulting in clean laser processing without overheating of the surrounding area.

  19. Revealing Nanostructures through Plasmon Polarimetry.

    Science.gov (United States)

    Kleemann, Marie-Elena; Mertens, Jan; Zheng, Xuezhi; Cormier, Sean; Turek, Vladimir; Benz, Felix; Chikkaraddy, Rohit; Deacon, William; Lombardi, Anna; Moshchalkov, Victor V; Vandenbosch, Guy A E; Baumberg, Jeremy J

    2017-01-24

    Polarized optical dark-field spectroscopy is shown to be a versatile noninvasive probe of plasmonic structures that trap light to the nanoscale. Clear spectral polarization splittings are found to be directly related to the asymmetric morphology of nanocavities formed between faceted gold nanoparticles and an underlying gold substrate. Both experiment and simulation show the influence of geometry on the coupled system, with spectral shifts Δλ = 3 nm from single atoms. Analytical models allow us to identify the split resonances as transverse cavity modes, tightly confined to the nanogap. The direct correlation of resonance splitting with atomistic morphology allows mapping of subnanometre structures, which is crucial for progress in extreme nano-optics involving chemistry, nanophotonics, and quantum devices.

  20. Sorption properties of carbon nanostructures

    International Nuclear Information System (INIS)

    Eletskii, Aleksandr V

    2004-01-01

    The current status of research in sorption properties of carbon nanotubes (CNTs) is reviewed. The structural peculiarities of CNTs, determining their sorption characteristics, are considered. The mechanisms of sorption of gaseous and condensed substances by such structures are analyzed. Special attention is paid to the problem of using CNTs for storing hydrogen and other gaseous substances. Methods for filling CNTs with liquid materials, based on capillary phenomena and wetting the graphite surface of the CNT with liquids of various nature, are considered. Properties of 'peapods' formed as a result of filling single-walled CNTs with fullerene molecules are reviewed. Also considered are perspectives on the applied usage of the sorption properties of CNTs in electrochemical and fuel cells, and material storage devices, as well as for producing superminiature metallic conductors. (reviews of topical problems)

  1. Solar thermophotovoltaic system using nanostructures.

    Science.gov (United States)

    Ungaro, Craig; Gray, Stephen K; Gupta, Mool C

    2015-09-21

    This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is both easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids.

  2. Probing of O2 vacancy defects and correlated magnetic, electrical and photoresponse properties in indium-tin oxide nanostructures by spectroscopic techniques

    Science.gov (United States)

    Ghosh, Shyamsundar; Dev, Bhupendra Nath

    2018-05-01

    Indium-tin oxide (ITO) 1D nanostructures with tunable morphologies i.e. nanorods, nanocombs and nanowires are grown on c-axis (0 0 0 1) sapphire (Al2O3) substrate in oxygen deficient atmosphere through pulsed laser deposition (PLD) technique and the effect of oxygen vacancies on optical, electrical, magnetic and photoresponse properties is investigated using spectroscopic methods. ITO nanostructures are found to be enriched with significant oxygen vacancy defects as evident from X-ray photoelectron and Raman spectroscopic analysis. Photoluminescence spectra exhibited intense mid-band blue emission at wavelength of region of 400-450 nm due to the electronic transition from conduction band maxima (CBM) to the singly ionized oxygen-vacancy (VO+) defect level within the band-gap. Interestingly, ITO nanostructures exhibited significant room-temperature ferromagnetism (RTFM) and the magnetic moment found proportional to concentration of VO+ defects which indicates VO+ defects are mainly responsible for the observed RTFM in nanostructures. ITO nanowires being enriched with more VO+ defects exhibited strongest RTFM as compared to other morphologies. Current voltage (I-V) characteristics of ITO nanostructures showed an enhancement of current under UV light as compared to dark which indicates such 1D nanostructure can be used as photovoltaic material. Hence, the study shows that there is ample opportunity to tailor the properties of ITOs through proper defect engineering's and such photosensitive ferromagnetic semiconductors might be promising for spintronic and photovoltaic applications.

  3. Highly mesoporous α-Fe2O3 nanostructures: preparation, characterization and improved photocatalytic performance towards Rhodamine B (RhB)

    International Nuclear Information System (INIS)

    Bharathi, S; Nataraj, D; Mangalaraj, D; Masuda, Y; Senthil, K; Yong, K

    2010-01-01

    Single-crystalline porous hematite nanorods and spindle-like nanostructures were successfully synthesized by a low temperature reflux condensation method. Two different iron sources, namely, FeCl 3 ·6H 2 O and Fe(NO 3 ) 3 ·9H 2 O, were hydrolyzed in the presence of urea to selectively prepare nanorods and spindle-like nanostructures. Initially, the akagenite phase was obtained by refluxing the precursor for 12 h and then the as-prepared akagenite nanostructures were transformed to porous hematite nanostructures upon calcination at 300 0 C for 1 h. The shape and the aspect ratio of the 12 h refluxed sample was retained even after calcination and this shows the topotactic transformation of the nanostructure. TEM and HRTEM investigations have shown the porous nature of the prepared sample. Brunauer-Emmett-Teller and Barret-Joyner-Halenda measurements have shown a large surface area and distribution of mesopores in the nanorods sample. The photocatalytic activity of the prepared nanostructures towards RhB has reflected this variation in the pore size distribution and specific surface area, by showing a higher activity for the nanorods sample. Magnetic studies by VSM have shown a weak ferromagnetic behaviour in both the samples due to shape anisotropy.

  4. Highly mesoporous {alpha}-Fe{sub 2}O{sub 3} nanostructures: preparation, characterization and improved photocatalytic performance towards Rhodamine B (RhB)

    Energy Technology Data Exchange (ETDEWEB)

    Bharathi, S; Nataraj, D [Thin Films and Nanomaterials Lab, Department of Physics, Bharathiar University, Coimbatore 641046 (India); Mangalaraj, D [DRDO-BU Centre for Life Sciences, Bharathiar University, Coimbatore 641046 (India); Masuda, Y [National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560 (Japan); Senthil, K [Centre for Information Materials, Pohang University of Science and Technology, Pohang (Korea, Republic of); Yong, K, E-mail: de.natraj@gmail.co [Department of Chemical Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2010-01-13

    Single-crystalline porous hematite nanorods and spindle-like nanostructures were successfully synthesized by a low temperature reflux condensation method. Two different iron sources, namely, FeCl{sub 3{center_dot}}6H{sub 2}O and Fe(NO{sub 3}){sub 3{center_dot}}9H{sub 2}O, were hydrolyzed in the presence of urea to selectively prepare nanorods and spindle-like nanostructures. Initially, the akagenite phase was obtained by refluxing the precursor for 12 h and then the as-prepared akagenite nanostructures were transformed to porous hematite nanostructures upon calcination at 300 {sup 0}C for 1 h. The shape and the aspect ratio of the 12 h refluxed sample was retained even after calcination and this shows the topotactic transformation of the nanostructure. TEM and HRTEM investigations have shown the porous nature of the prepared sample. Brunauer-Emmett-Teller and Barret-Joyner-Halenda measurements have shown a large surface area and distribution of mesopores in the nanorods sample. The photocatalytic activity of the prepared nanostructures towards RhB has reflected this variation in the pore size distribution and specific surface area, by showing a higher activity for the nanorods sample. Magnetic studies by VSM have shown a weak ferromagnetic behaviour in both the samples due to shape anisotropy.

  5. The interplay between nanostructured carbon-grafted chitosan scaffolds and protein adsorption on the cellular response of osteoblasts: structure-function property relationship.

    Science.gov (United States)

    Depan, D; Misra, R D K

    2013-04-01

    The rapid adsorption of proteins occurs during the early stages of biomedical device implantation into physiological systems. In this regard, the adsorption of proteins is a strong function of the nature of a biomedical device, which ultimately governs the biological functions. The objective of this study was to elucidate the interplay between nanostructured carbon-modified (graphene oxide and single-walled carbon nanohorn) chitosan scaffolds and consequent protein adsorption and biological function (osteoblast function). We compare and contrast the footprint of protein adsorption on unmodified chitosan and nanostructured carbon-modified chitosan. A comparative analysis of cell-substrate interactions using an osteoblast cell line (MC3T3-E1) implied that biological functions were significantly enhanced in the presence of nanostructured carbon, compared with unmodified chitosan. The difference in their respective behaviors is related to the degree and topography of protein adsorption on the scaffolds. Furthermore, there was a synergistic effect of nanostructured carbon and protein adsorption in terms of favorably modulating biological functions, including cell attachment, proliferation and viability, with the effect being greater on nanostructured carbon-modified scaffolds. The study also underscores that protein adsorption is favored in nanostructured carbon-modified scaffolds such that bioactivity and biological function are promoted. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species.

    Science.gov (United States)

    Saranathan, Vinodkumar; Forster, Jason D; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G J; Cao, Hui; Dufresne, Eric R; Prum, Richard O

    2012-10-07

    Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.

  7. When lithography meets self-assembly: a review of recent advances in the directed assembly of complex metal nanostructures on planar and textured surfaces

    Science.gov (United States)

    Hughes, Robert A.; Menumerov, Eredzhep; Neretina, Svetlana

    2017-07-01

    One of the foremost challenges in nanofabrication is the establishment of a processing science that integrates wafer-based materials, techniques, and devices with the extraordinary physicochemical properties accessible when materials are reduced to nanoscale dimensions. Such a merger would allow for exacting controls on nanostructure positioning, promote cooperative phenomenon between adjacent nanostructures and/or substrate materials, and allow for electrical contact to individual or groups of nanostructures. With neither self-assembly nor top-down lithographic processes being able to adequately meet this challenge, advancements have often relied on a hybrid strategy that utilizes lithographically-defined features to direct the assembly of nanostructures into organized patterns. While these so-called directed assembly techniques have proven viable, much of this effort has focused on the assembly of periodic arrays of spherical or near-spherical nanostructures comprised of a single element. Work directed toward the fabrication of more complex nanostructures, while still at a nascent stage, has nevertheless demonstrated the possibility of forming arrays of nanocubes, nanorods, nanoprisms, nanoshells, nanocages, nanoframes, core-shell structures, Janus structures, and various alloys on the substrate surface. In this topical review, we describe the progress made in the directed assembly of periodic arrays of these complex metal nanostructures on planar and textured substrates. The review is divided into three broad strategies reliant on: (i) the deterministic positioning of colloidal structures, (ii) the reorganization of deposited metal films at elevated temperatures, and (iii) liquid-phase chemistry practiced directly on the substrate surface. These strategies collectively utilize a broad range of techniques including capillary assembly, microcontact printing, chemical surface modulation, templated dewetting, nanoimprint lithography, and dip-pen nanolithography and

  8. Molecular threading and tunable molecular recognition on DNA origami nanostructures.

    Science.gov (United States)

    Wu, Na; Czajkowsky, Daniel M; Zhang, Jinjin; Qu, Jianxun; Ye, Ming; Zeng, Dongdong; Zhou, Xingfei; Hu, Jun; Shao, Zhifeng; Li, Bin; Fan, Chunhai

    2013-08-21

    The DNA origami technology holds great promise for the assembly of nanoscopic technological devices and studies of biochemical reactions at the single-molecule level. For these, it is essential to establish well controlled attachment of functional materials to predefined sites on the DNA origami nanostructures for reliable measurements and versatile applications. However, the two-sided nature of the origami scaffold has shown limitations in this regard. We hypothesized that holes of the commonly used two-dimensional DNA origami designs are large enough for the passage of single-stranded (ss)-DNA. Sufficiently long ssDNA initially located on one side of the origami should thus be able to "thread" to the other side through the holes in the origami sheet. By using an origami sheet attached with patterned biotinylated ssDNA spacers and monitoring streptavidin binding with atomic force microscopic (AFM) imaging, we provide unambiguous evidence that the biotin ligands positioned on one side have indeed threaded through to the other side. Our finding reveals a previously overlooked critical design feature that should provide new interpretations to previous experiments and new opportunities for the construction of origami structures with new functional capabilities.

  9. Transport Measurements on Si Nanostructures with Counted Sb Donors

    Science.gov (United States)

    Singh, Meenakshi; Bielejec, Edward; Garratt, Elias; Ten Eyck, Gregory; Bishop, Nathaniel; Wendt, Joel; Luhman, Dwight; Carroll, Malcolm; Lilly, Michael

    2014-03-01

    Donor based spin qubits are a promising platform for quantum computing. Single qubits using timed implant of donors have been demonstrated.1 Extending this to multiple qubits requires precise control over the placement and number of donors. Such control can be achieved by using a combination of low-energy heavy-ion implants (to reduce depth straggle), electron-beam lithography (to define position), focused ion beam (to localize implants to one lithographic site) and counting the number of implants with a single ion detector.2 We report transport measurements on MOS quantum dots implanted with 5, 10 and 20 Sb donors using the approach described above. A donor charge transition is identified by a charge offset in the transport characteristics. Correlation between the number of donors and the charge offsets is studied. These results are necessary first steps towards fabricating donor nanostructures for two qubit interactions. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. The work was supported by Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000. 1J. J. Pla et al., Nature 496, 334 (2013) 2J. A. Seamons et al., APL 93, 043124 (2008).

  10. Optical bandgap of semiconductor nanostructures: Methods for experimental data analysis

    Science.gov (United States)

    Raciti, R.; Bahariqushchi, R.; Summonte, C.; Aydinli, A.; Terrasi, A.; Mirabella, S.

    2017-06-01

    Determination of the optical bandgap (Eg) in semiconductor nanostructures is a key issue in understanding the extent of quantum confinement effects (QCE) on electronic properties and it usually involves some analytical approximation in experimental data reduction and modeling of the light absorption processes. Here, we compare some of the analytical procedures frequently used to evaluate the optical bandgap from reflectance (R) and transmittance (T) spectra. Ge quantum wells and quantum dots embedded in SiO2 were produced by plasma enhanced chemical vapor deposition, and light absorption was characterized by UV-Vis/NIR spectrophotometry. R&T elaboration to extract the absorption spectra was conducted by two approximated methods (single or double pass approximation, single pass analysis, and double pass analysis, respectively) followed by Eg evaluation through linear fit of Tauc or Cody plots. Direct fitting of R&T spectra through a Tauc-Lorentz oscillator model is used as comparison. Methods and data are discussed also in terms of the light absorption process in the presence of QCE. The reported data show that, despite the approximation, the DPA approach joined with Tauc plot gives reliable results, with clear advantages in terms of computational efforts and understanding of QCE.

  11. Metal oxide core shell nanostructures as building blocks for efficient light emission (SISGR)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jane P [Univ. of California, Los Angeles, CA (United States); Dorman, James [Univ. of California, Los Angeles, CA (United States); Cheung, Cyrus [Univ. of California, Los Angeles, CA (United States)

    2016-01-12

    The objective of this research is to synthesize core-shell nano-structured metal oxide materials and investigate their structural, electronic and optical properties to understand the microscopic pathways governing the energy conversion process, thereby controlling and improving their efficiency. Specifically, the goal is to use a single metal oxide core-shell nanostructure and a single excitation source to generate photons with long emission lifetime over the entire visible spectrum and when controlled at the right ratio, generating white light. In order to achieve this goal, we need to control the energy transfer between light emitting elements, which dictates the control of their interatomic spacing and spatial distribution. We developed an economical wet chemical process to form the nanostructured core and to control the thickness and composition of the shell layers. With the help from using DOE funded synchrotron radiation facility, we delineated the growth mechanism of the nano-structured core and the shell layers, thereby enhancing our understanding of structure-property relation in these materials. Using the upconversion luminescence and the lifetime measurements as effective feedback to materials sysnthes is and integration, we demonstrated improved luminescence lifetimes of the core-shell nano-structures and quantified the optimal core-multi-shell structure with optimum shell thickness and composition. We developed a rare-earths co-doped LaPO4 core-multishell structure in order to produce a single white light source. It was decided that the mutli-shell method would produce the largest increase in luminescence efficiency while limiting any energy transfer that may occur between the dopant ions. All samples resulted in emission spectra within the accepted range of white light generation based on the converted CIE color coordinates. The white light obtained varied between warm and cool white depending on the layering architecture, allowing for the

  12. Novel Biomedical Device Utilizing Light-Emitting Nanostructures Developed

    Science.gov (United States)

    Scardelletti, Maximilian C.; Goldman, Rachel

    2004-01-01

    Sketches and chemical diagrams of state-of-the-art device and novel proposed device are presented. Current device uses a diode laser that emits into a fluorescent fluid only one wavelength and a photodetector diode that detects only one wavelength. Only one type of bacteria can be detected. The proposed device uses a quantum dot array that emits into a fluorescent fluid multiple wavelengths and an NIR 512 spectrometer that scans 0.8- to 1.7-mm wavelengths. Hundreds of different bacteria and viruses can be detected. A novel biomedical device is being developed at the NASA Glenn Research Center in cooperation with the University of Michigan. This device uses nano-structured quantum dots that emit light in the near-infrared (IR) region. The nanostructured quantum dots are used as a source and excite fluorochrome polymers coupled with antibodies that seek out and attach to specific bacteria and viruses. The fluorochrome polymers/antibodies fluoresce at specific wavelengths in the near-IR spectrum, but these wavelengths are offset from the excitation wavelength and can be detected with a tunable spectrometer. The device will be used to detect the presence of viruses and bacteria in simple fluids and eventually in more complex fluids, such as blood. Current state-of-the-art devices are limited to single bacteria or virus detection and a considerable amount of time and effort is required to prepare samples for analysis. Most importantly, the devices are quite large and cumbersome, which prohibits them from being used on the International Space Station and the space shuttles. This novel device uses nanostructured quantum dots which, through molecular beam epitaxy and highly selective annealing processes, can be developed into an illumination source that could potentially generate hundreds of specific wavelengths. As a result, this device will be able to excite hundreds of antibody/fluorochrome polymer combinations, which in turn could be used to detect hundreds of bacteria

  13. Heat Transfer from Optically Excited Gold Nanostructures into Water, Sugar, and Salt Solutions

    Science.gov (United States)

    Green, Andrew J.

    Nanotechnology has introduced a wide variety of new behaviors to study and understand. Metal nanostructures are of particular interest due to their ability to generate large amounts of heat when irradiated at the plasmon resonance. Furthermore, heat dissipation at the nanoscale becomes exceedingly more complicated with respect to bulk behavior. What are the credentials for a heat carrier to move across an interface? Is it important for both materials to have similar vibrational density of states? What changes if one material is a liquid? All of these questions have open ended answers, each of which hold potential for new technologies to be exploited once understood. This dissertation will discuss topics exploring the transfer of heat from an optically excited gold nanoparticle into a surrounding liquid. Gold nanostructures are created using conventional electron beam lithography with lift-off. The nanostructures are deposited onto a thin film thermal sensor composed of AlGaN:Er3+. Erbium(III) has two thermally coupled excited states that can be excited with a 532nm laser. The relative photoluminescence from these excited states are related by a Boltzmann factor and are thusly temperature dependent. A scanning optical microscope collects an image of Er3+ photoluminescence while simultaneously exciting the gold nanostructure. The nanostructure temperature is imaged which is directly related to the surrounding's heat dissipation properties. The first of two topics discuss the heat dissipation and phase change properties of water. A gold nanostructure is submersed under water and subsequently heated with a 532 nm laser. The water immediately surrounding the nanodot is can be superheated beyond the boiling point up to the spinodal decomposition temperature at 594 +/- 17 K. The spinodal decomposition has been confirmed with the observation of critical opalescence. We characterize the laser scattering that occurs in unison with spinodal decomposition due to an increased

  14. Superhydrophobic multi-scale ZnO nanostructures fabricated by chemical vapor deposition method.

    Science.gov (United States)

    Zhou, Ming; Feng, Chengheng; Wu, Chunxia; Ma, Weiwei; Cai, Lan

    2009-07-01

    The ZnO nanostructures were synthesized on Si(100) substrates by chemical vapor deposition (CVD) method. Different Morphologies of ZnO nanostructures, such as nanoparticle film, micro-pillar and micro-nano multi-structure, were obtained with different conditions. The results of XRD and TEM showed the good quality of ZnO crystal growth. Selected area electron diffraction analysis indicates the individual nano-wire is single crystal. The wettability of ZnO was studied by contact angle admeasuring apparatus. We found that the wettability can be changed from hydrophobic to super-hydrophobic when the structure changed from smooth particle film to single micro-pillar, nano-wire and micro-nano multi-scale structure. Compared with the particle film with contact angle (CA) of 90.7 degrees, the CA of single scale microstructure and sparse micro-nano multi-scale structure is 130-140 degrees, 140-150 degrees respectively. But when the surface is dense micro-nano multi-scale structure such as nano-lawn, the CA can reach to 168.2 degrees . The results indicate that microstructure of surface is very important to the surface wettability. The wettability on the micro-nano multi-structure is better than single-scale structure, and that of dense micro-nano multi-structure is better than sparse multi-structure.

  15. Schottky nanocontact of one-dimensional semiconductor nanostructures probed by using conductive atomic force microscopy

    Science.gov (United States)

    Lee, Jung Ah; Rok Lim, Young; Jung, Chan Su; Choi, Jun Hee; Im, Hyung Soon; Park, Kidong; Park, Jeunghee; Kim, Gyu Tae

    2016-10-01

    To develop the advanced electronic devices, the surface/interface of each component must be carefully considered. Here, we investigate the electrical properties of metal-semiconductor nanoscale junction using conductive atomic force microscopy (C-AFM). Single-crystalline CdS, CdSe, and ZnO one-dimensional nanostructures are synthesized via chemical vapor transport, and individual nanobelts (or nanowires) are used to fabricate nanojunction electrodes. The current-voltage (I -V) curves are obtained by placing a C-AFM metal (PtIr) tip as a movable contact on the nanobelt (or nanowire), and often exhibit a resistive switching behavior that is rationalized by the Schottky (high resistance state) and ohmic (low resistance state) contacts between the metal and semiconductor. We obtain the Schottky barrier height and the ideality factor through fitting analysis of the I-V curves. The present nanojunction devices exhibit a lower Schottky barrier height and a higher ideality factor than those of the bulk materials, which is consistent with the findings of previous works on nanostructures. It is shown that C-AFM is a powerful tool for characterization of the Schottky contact of conducting channels between semiconductor nanostructures and metal electrodes.

  16. Tip Enhanced Raman Spectroscopy of Rhodamine 6G on nanostructured gold substrate

    KAUST Repository

    Moretti, Manola

    2015-05-01

    A new concept based setup for Tip Enhanced Raman Scattering measurement assisted by gold nanostructure is presented, that can provide a platform for gap-mode enhancement of the signal at the single molecule level conjugated with controlled spatial localization of the molecule under investigation and a method to determine the diffraction limit properties of the tip. In essence, this effect is obtained illuminating a gold coated AFM tip which is raster scanned over a nanostructured gold substrate, after chemisorption of a Raman active molecule. We expect that the near-field Raman enhancement would be given by the gap-mode effect of the two facing nano-features. Thanks to the nanostructured substrate, we verify that the resolution of the Raman mapping signal is well below the diffraction limit given by the combination of the optics geometry and the laser wavelength. We show that the gap-mode TERS can generate an estimated field- enhancement (g) of ~20 in localized areas of the sample and we demonstrate the ability to spatially define the molecule position (by Raman mapping) at the tens of nanometers scale. © 2015 Elsevier Ltd.

  17. Complex Nanostructures from Materials based on Metal-Organic Frameworks for Electrochemical Energy Storage and Conversion.

    Science.gov (United States)

    Guan, Bu Yuan; Yu, Xin Yao; Wu, Hao Bin; Lou, Xiong Wen David

    2017-12-01

    Metal-organic frameworks (MOFs) have drawn tremendous attention because of their abundant diversity in structure and composition. Recently, there has been growing research interest in deriving advanced nanomaterials with complex architectures and tailored chemical compositions from MOF-based precursors for electrochemical energy storage and conversion. Here, a comprehensive overview of the synthesis and energy-related applications of complex nanostructures derived from MOF-based precursors is provided. After a brief summary of synthetic methods of MOF-based templates and their conversion to desirable nanostructures, delicate designs and preparation of complex architectures from MOFs or their composites are described in detail, including porous structures, single-shelled hollow structures, and multishelled hollow structures, as well as other unusual complex structures. Afterward, their applications are discussed as electrode materials or catalysts for lithium-ion batteries, hybrid supercapacitors, water-splitting devices, and fuel cells. Lastly, the research challenges and possible development directions of complex nanostructures derived from MOF-based-templates for electrochemical energy storage and conversion applications are outlined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Study of resonant processes in plasmonic nanostructures for sensor applications (Conference Presentation)

    Science.gov (United States)

    Pirunčík, Jiří; Kwiecien, Pavel; Fiala, Jan; Richter, Ivan

    2017-05-01

    This contribution is focused on the numerical studies of resonant processes in individual plasmonic nanostructures, with the attention particularly given to rectangular nanoparticles and concominant localized surface plasmon resonance processes. Relevant models for the description and anylysis of localized surface plasmon resonance are introduced, in particular: quasistatic approximation, Mie theory and in particular, a generalized (quasi)analytical approach for treating rectangularly shaped nanostructures. The parameters influencing resonant behavior of nanoparticles are analyzed with special interest in morphology and sensor applications. Results acquired with Lumerical FDTD Solutions software, using finite-difference time-domain simulation method, are shown and discussed. Simulations were mostly performed for selected nanostructures composed of finite rectangular nanowires with square cross-sections. Systematic analysis is made for single nanowires with varying length, parallel couple of nanowires with varying gap (cut -wires) and selected dolmen structures with varying gap between one nanowire transversely located with respect to parallel couple of nanowires (in both in-plane and -out-of-plane arrangements). The dependence of resonant peaks of cross-section spectral behavior (absorption, scattering, extinction) and their tunability via suitable structuring and morphology changes are primarily researched. These studies are then followed with an analysis of the effect of periodic arrangements. The results can be usable with respect to possible sensor applications.

  19. Nanostructured materials with plasmonic nanobiosensors for early cancer detection: A past and future prospect.

    Science.gov (United States)

    Sugumaran, Sathish; Jamlos, Mohd Faizal; Ahmad, Mohd Noor; Bellan, Chandar Shekar; Schreurs, Dominique

    2018-02-15

    Early cancer detection and treatment is an emerging and fascinating field of plasmonic nanobiosensor research. It paves to enrich a life without affecting living cells leading to a possible survival of the patient. This review describes a past and future prospect of an integrated research field on nanostructured metamaterials, microwave transmission, surface plasmonic resonance, nanoantennas, and their manifested versatile properties with nano-biosensors towards early cancer detection to preserve human health. Interestingly, (i) microwave transmission shows more advantages than other electromagnetic radiation in reacting with biological tissues, (ii) nanostructured metamaterial (Au) with special properties like size and shape can stimulate plasmonic effects, (iii) plasmonic based nanobiosensors are to explore the efficacy for early cancer tumour detection or single molecular detection and (iv) nanoantenna wireless communication by using microwave inverse scattering nanomesh (MISN) technique instead of conventional techniques can be adopted to characterize the microwave scattered signals from the biomarkers. It reveals that the nanostructured material with plasmonic nanobiosensor paves a fascinating platform towards early detection of cancer tumour and is anticipated to be exploited as a magnificent field in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Hyperbranched quasi-1D nanostructures for solid-state dye-sensitized solar cells.

    Science.gov (United States)

    Passoni, Luca; Ghods, Farbod; Docampo, Pablo; Abrusci, Agnese; Martí-Rujas, Javier; Ghidelli, Matteo; Divitini, Giorgio; Ducati, Caterina; Binda, Maddalena; Guarnera, Simone; Li Bassi, Andrea; Casari, Carlo Spartaco; Snaith, Henry J; Petrozza, Annamaria; Di Fonzo, Fabio

    2013-11-26

    In this work we demonstrate hyperbranched nanostructures, grown by pulsed laser deposition, composed of one-dimensional anatase single crystals assembled in arrays of high aspect ratio hierarchical mesostructures. The proposed growth mechanism relies on a two-step process: self-assembly from the gas phase of amorphous TiO2 clusters in a forest of tree-shaped hierarchical mesostructures with high aspect ratio; oriented crystallization of the branches upon thermal treatment. Structural and morphological characteristics can be optimized to achieve both high specific surface area for optimal dye uptake and broadband light scattering thanks to the microscopic feature size. Solid-state dye sensitized solar cells fabricated with arrays of hyperbranched TiO2 nanostructures on FTO-glass sensitized with D102 dye showed a significant 66% increase in efficiency with respect to a reference mesoporous photoanode and reached a maximum efficiency of 3.96% (among the highest reported for this system). This result was achieved mainly thanks to an increase in photogenerated current directly resulting from improved light harvesting efficiency of the hierarchical photoanode. The proposed photoanode overcomes typical limitations of 1D TiO2 nanostructures applied to ss-DSC and emerges as a promising foundation for next-generation high-efficiency solid-state devices comprosed of dyes, polymers, or quantum dots as sensitizers.

  1. Tip Enhanced Raman Spectroscopy of Rhodamine 6G on nanostructured gold substrate

    KAUST Repository

    Moretti, Manola; Das, Gobind; Torre, Bruno; Allione, Marco; Di Fabrizio, Enzo M.

    2015-01-01

    A new concept based setup for Tip Enhanced Raman Scattering measurement assisted by gold nanostructure is presented, that can provide a platform for gap-mode enhancement of the signal at the single molecule level conjugated with controlled spatial localization of the molecule under investigation and a method to determine the diffraction limit properties of the tip. In essence, this effect is obtained illuminating a gold coated AFM tip which is raster scanned over a nanostructured gold substrate, after chemisorption of a Raman active molecule. We expect that the near-field Raman enhancement would be given by the gap-mode effect of the two facing nano-features. Thanks to the nanostructured substrate, we verify that the resolution of the Raman mapping signal is well below the diffraction limit given by the combination of the optics geometry and the laser wavelength. We show that the gap-mode TERS can generate an estimated field- enhancement (g) of ~20 in localized areas of the sample and we demonstrate the ability to spatially define the molecule position (by Raman mapping) at the tens of nanometers scale. © 2015 Elsevier Ltd.

  2. Magnetization jumps in nanostructured Nd–Fe–B alloy at low temperatures

    International Nuclear Information System (INIS)

    Neznakhin, D.S.; Bolyachkin, A.S.; Volegov, A.S.; Markin, P.E.; Andreev, S.V.; Kudrevatykh, N.V.

    2015-01-01

    Magnetic properties of the nanostructured isotropic alloy on the base of Nd 2 Fe 14 B type phase were investigated at low temperatures. The evaluated average grain size of this phase was much smaller than its critical single domain diameter. Hence the magnetization and demagnetization processes were expected to be performed by coherent magnetization rotation. For such coercivity type system magnetization jumps were revealed on the demagnetization hysteresis loop branch in the vicinity of the coercive force at temperatures below 4 K. It was shown that magnetization jumps have a stochastic behavior and their number strongly depends on the temperature and the mass of measured samples. High temperature spikes corresponding to magnetization discontinuities were observed. All these results allowed to propose that magnetization jumps in nanostructured magnetics with magnetization rotation reversal processes comply with the local heating model. - Highlights: • Magnetization reversals of the nanostructured Nd–Fe–B-type alloy were obtained below 4 K. • Magnetization jumps were first observed for magnetization rotation coercivity type magnets. • Staircase magnetization reversal was explained within the framework of the local heating model

  3. Nanostructured carbon materials based electrothermal air pump actuators

    Science.gov (United States)

    Liu, Qing; Liu, Luqi; Kuang, Jun; Dai, Zhaohe; Han, Jinhua; Zhang, Zhong

    2014-05-01

    Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with common polymer nanocomposites based electrothermal actuators, our actuators exhibited better actuation performances with a low driving voltage (film actuator due to the intrinsic gas-impermeability nature of graphene platelets. In addition, the high modulus of the r-GO and GO/SWCNT films also guaranteed the large generated stress and high work density. Specifically, the generated stress and gravimetric work density of the GO/SWCNT hybrid film actuator could reach up to more than 50 MPa and 30 J kg-1, respectively, under a driving voltage of 10 V. The resulting stress value is at least two orders of magnitude higher than that of natural muscles (~0.4 MPa).Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with

  4. Progress and Design Concerns of Nanostructured Solar Energy Harvesting Devices.

    Science.gov (United States)

    Leung, Siu-Fung; Zhang, Qianpeng; Tavakoli, Mohammad Mahdi; He, Jin; Mo, Xiaoliang; Fan, Zhiyong

    2016-05-01

    Integrating devices with nanostructures is considered a promising strategy to improve the performance of solar energy harvesting devices such as photovoltaic (PV) devices and photo-electrochemical (PEC) solar water splitting devices. Extensive efforts have been exerted to improve the power conversion efficiencies (PCE) of such devices by utilizing novel nanostructures to revolutionize device structural designs. The thicknesses of light absorber and material consumption can be substantially reduced because of light trapping with nanostructures. Meanwhile, the utilization of nanostructures can also result in more effective carrier collection by shortening the photogenerated carrier collection path length. Nevertheless, performance optimization of nanostructured solar energy harvesting devices requires a rational design of various aspects of the nanostructures, such as their shape, aspect ratio, periodicity, etc. Without this, the utilization of nanostructures can lead to compromised device performance as the incorporation of these structures can result in defects and additional carrier recombination. The design guidelines of solar energy harvesting devices are summarized, including thin film non-uniformity on nanostructures, surface recombination, parasitic absorption, and the importance of uniform distribution of photo-generated carriers. A systematic view of the design concerns will assist better understanding of device physics and benefit the fabrication of high performance devices in the future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Nanostructured Materials for Li-Ion Batteries and Beyond

    Directory of Open Access Journals (Sweden)

    Xifei Li

    2016-04-01

    Full Text Available This Special Issue “Nanostructured Materials for Li-Ion Batteries and Beyond” of Nanomaterials is focused on advancements in the synthesis, optimization, and characterization of nanostructured materials, with an emphasis on the application of nanomaterials for building high performance Li-ion batteries (LIBs and future systems.[...

  6. Preparation and characterization of GA/RDX nanostructured ...

    Indian Academy of Sciences (India)

    Thenhexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was added and trapped in the nano-porous three-dimensional networks of GA to obtain a novel GA/RDX nanostructured energetic composite. The composition, morphology andstructure of the obtained GA/RDX nanostructured energetic composite were characterized by ...

  7. Enhancement of Light-Matter Interaction in Semiconductor Nanostructures

    DEFF Research Database (Denmark)

    Stobbe, Søren

    This thesis reports research on enhancement of light-matter interaction in semi- conductor quantum nanostructures by means of nanostructure fabrication, optical measurements, and theoretical modeling. Photonic crystal membranes of very high quality and samples for studies of quantum dots in proxi......-matter interaction is investigated. For the rst time the vacuum Rabi splitting is observed in an electrically tunable device....

  8. The investigation of nanostructures of magnetic recording media by TEM

    International Nuclear Information System (INIS)

    Peng Yingguo; Ohkubo, Tadakatsu; Laughlin, David E.

    2003-01-01

    Diverse applications of transmission electron microscopy techniques used in investigating the nanostructures of magnetic recording materials are presented. Specimen preparation methods are discussed for the specific case of magnetic thin film recording media. Investigations of the crystallographic orientation, grain size and distribution, and interfacial nanostructures are presented

  9. Microwave-Assisted Green Synthesis of Silver Nanostructures

    Science.gov (United States)

    This account summarizes a microwave (MW)-assisted synthetic approach for producing silver nanostructures. The rapid and in-core MW heating has received considerable attention as a promising new method for the one-pot synthesis of metallic nanostructures in solutions. Conceptually...

  10. Terahertz carrier dynamics in graphene and graphene nanostructures

    DEFF Research Database (Denmark)

    Jensen, Søren A.; Turchinovich, Dmitry; Tielrooij, Klaas Jan

    2014-01-01

    Photoexcited charge carriers in 2D graphene and in 1D graphene nanostructures were studied with optical pump-THz probe spectroscopy. We find efficient hot-carrier multiplication in 2D graphene, and predominantly free carrier early time response in 1D nanostructures. © 2014 OSA....

  11. Mapping of electromagnetic fields enhanced by gold nanostructures

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kostiučenko, Oksana

    2012-01-01

    Laser ablation of an ‘imaging’ polymer layer allows near-field mapping of metal nanostructures with subdiffraction resolution......Laser ablation of an ‘imaging’ polymer layer allows near-field mapping of metal nanostructures with subdiffraction resolution...

  12. Metal-organic framework templated electrodeposition of functional gold nanostructures

    International Nuclear Information System (INIS)

    Worrall, Stephen D.; Bissett, Mark A.; Hill, Patrick I.; Rooney, Aidan P.; Haigh, Sarah J.; Attfield, Martin P.; Dryfe, Robert A.W.

    2016-01-01

    Highlights: • Electrodeposition of anisotropic Au nanostructures templated by HKUST-1. • Au nanostructures replicate ∼1.4 nm pore spaces of HKUST-1. • Encapsulated Au nanostructures active as SERS substrate for 4-fluorothiophenol. - Abstract: Utilizing a pair of quick, scalable electrochemical processes, the permanently porous MOF HKUST-1 was electrochemically grown on a copper electrode and this HKUST-1-coated electrode was used to template electrodeposition of a gold nanostructure within the pore network of the MOF. Transmission electron microscopy demonstrates that a proportion of the gold nanostructures exhibit structural features replicating the pore space of this ∼1.4 nm maximum pore diameter MOF, as well as regions that are larger in size. Scanning electron microscopy shows that the electrodeposited gold nanostructure, produced under certain conditions of synthesis and template removal, is sufficiently inter-grown and mechanically robust to retain the octahedral morphology of the HKUST-1 template crystals. The functionality of the gold nanostructure within the crystalline HKUST-1 was demonstrated through the surface enhanced Raman spectroscopic (SERS) detection of 4-fluorothiophenol at concentrations as low as 1 μM. The reported process is confirmed as a viable electrodeposition method for obtaining functional, accessible metal nanostructures encapsulated within MOF crystals.

  13. Dynamic Processes in Nanostructured Crystals Under Ion Irradiation

    Science.gov (United States)

    Uglov, V. V.; Kvasov, N. T.; Shimanski, V. I.; Safronov, I. V.; Komarov, N. D.

    2018-02-01

    The paper presents detailed investigations of dynamic processes occurring in nanostructured Si(Fe) material under the radiation exposure, namely: heating, thermoelastic stress generation, elastic disturbances of the surrounding medium similar to weak shock waves, and dislocation generation. The performance calculations are proposed for elastic properties of the nanostructured material with a glance to size effects in nanoparticles.

  14. Coherent excitonic nonlinearity versus inhomogeneous broadening in single quantum wells

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Borri, Paola; Hvam, Jørn Märcher

    1998-01-01

    The coherent response of excitons in semiconductor nanostructures, as measured in four wave mixing (FWM) experiments, depends strongly on the inhomogeneous broadening of the exciton transition. We investigate GaAs-AlGaAs single quantum wells (SQW) of 4 nm to 25 nm well width. Two main mechanisms...

  15. METHOD FOR MANUFACTURING A SINGLE CRYSTAL NANO-WIRE

    NARCIS (Netherlands)

    Van Den Berg, Albert; Bomer, Johan; Carlen Edwin, Thomas; Chen, Songyue; Kraaijenhagen Roderik, Adriaan; Pinedo Herbert, Michael

    2012-01-01

    A method for manufacturing a single crystal nano-structure includes providing a device layer with a 100 structure on a substrate; providing a stress layer onto the device layer; patterning the stress layer along the 110 direction of the device layer; selectively removing parts of the stress layer to

  16. METHOD FOR MANUFACTURING A SINGLE CRYSTAL NANO-WIRE.

    NARCIS (Netherlands)

    Van Den Berg, Albert; Bomer, Johan; Carlen Edwin, Thomas; Chen, Songyue; Kraaijenhagen Roderik, Adriaan; Pinedo Herbert, Michael

    2011-01-01

    A method for manufacturing a single crystal nano-structure is provided comprising the steps of providing a device layer with a 100 structure on a substrate; providing a stress layer onto the device layer; patterning the stress layer along the 110 direction of the device layer; selectively removing

  17. Silk fibroin nanostructured materials for biomedical applications

    Science.gov (United States)

    Mitropoulos, Alexander N.

    Nanostructured biopolymers have proven to be promising to develop novel biomedical applications where forming structures at the nanoscale normally occurs by self-assembly. However, synthesizing these structures can also occur by inducing materials to transition into other forms by adding chemical cross-linkers, changing pH, or changing ionic composition. Understanding the generation of nanostructures in fluid environments, such as liquid organic solvents or supercritical fluids, has not been thoroughly examined, particularly those that are based on protein-based block-copolymers. Here, we examine the transformation of reconstituted silk fibroin, which has emerged as a promising biopolymer due to its biocompatibility, biodegradability, and ease of functionalization, into submicron spheres and gel networks which offer applications in tissue engineering and advanced sensors. Two types of gel networks, hydrogels and aerogels, have small pores and large surface areas that are defined by their structure. We design and analyze silk nanoparticle formation using a microfluidic device while offering an application for drug delivery. Additionally, we provide a model and characterize hydrogel formation from micelles to nanoparticles, while investigating cellular response to the hydrogel in an in vitro cell culture model. Lastly, we provide a second model of nanofiber formation during near-critical and supercritical drying and characterize the silk fibroin properties at different drying pressures which, when acting as a stabilizing matrix, shows to improve the activity of entrapped enzymes dried at different pressures. This work has created new nanostructured silk fibroin forms to benefit biomedical applications that could be applied to other fibrous proteins.

  18. TOPICAL REVIEW: Vicinal surfaces for functional nanostructures

    Science.gov (United States)

    Tegenkamp, Christoph

    2009-01-01

    Vicinal surfaces are currently the focus of research. The regular arrangements of atomic steps on a mesoscopic scale reveal the possibility to functionalize these surfaces for technical applications, e.g. nanowires, catalysts, etc. The steps of the vicinal surface are well-defined defect structures of atomic size for nucleation of low-dimensional nanostructures. The concentration and therefore the coupling between the nanostructures can be tuned over a wide range by simply changing the inclination angle of the substrate. However, the coupling of these nano-objects to the substrate is just as important in controlling their electronic or chemical properties and making a functionality useable. On the basis of stepped insulating films, these aspects are fulfilled and will be considered in the first part of this review. Recent results for the epitaxial growth of wide bandgap insulating films (CaF2, MgO, NaCl, BaSrO) on metallic and semiconducting vicinal substrates (Si(100), Ge(100), Ag(100)) will be presented. The change of the electronic structure, the adsorption behavior as well as the kinetics and energetics of color centers in the presence of steps is discussed. The successful bridging of the gap between the atomic and mesoscopic world, i.e. the functionalization of vicinal surfaces by nanostructures, is demonstrated in the second part by metal adsorption on semiconducting surfaces. For (sub)monolayer coverage these systems have in common that the surface states do not hybridize with the support, i.e. the semiconducting surfaces are insulating. Here I will focus on the latest results of macroscopic transport measurements on Pb quantum wires grown on vicinal Si(111) showing indeed a one-dimensional transport behavior.

  19. Ultraflexible nanostructures and implications for future nanorobots

    Science.gov (United States)

    Cohn, Robert W.; Panchapakesan, Balaji

    2016-05-01

    Several high aspect ratio nanostructures have been made by capillary force directed self-assembly including polymeric nanofiber air-bridges, trampoline-like membranes, microsphere-beaded nanofibers, and intermetallic nanoneedles. Arrays of polymer air-bridges form in seconds by simply hand brushing a bead of polymeric liquid over an array of micropillars. The domination of capillary force that is thinning unstable capillary bridges leads to uniform arrays of nanofiber air-bridges. Similarly, arrays of vertically oriented Ag2Ga nanoneedles have been formed by dipping silvercoated arrays of pyramidal silicon into melted gallium. Force-displacement measurements of these structures are presented. These nanostructures, especially when compressively or torsionally buckled, have extremely low stiffnesses, motion due to thermal fluctuations that is relatively easily detected, and the ability to move great distances for very small changes in applied force. Nanofibers with bead-on-a-string structure, where the beads are micron diameter and loaded with magnetic iron oxide (maghemite), are shown to be simply viewable under optical microscopes, have micronewton/ m stiffness, and have ultralow torsional stiffnesses enabling the bead to be rotated numerous revolutions without breaking. Combination of these high aspect ratio structures with stretched elastomers offer interesting possibilities for robotic actuation and locomotion. Polydimethylsiloxane loaded with nanomaterials, e.g. nanotubes, graphene or MoS2, can be efficiently heated with directed light. Heating produces considerable force through the thermoelastic effect, and this force can be used for continuous translation or to trigger reversible elastic buckling of the nanostructures. The remote stimulation of motion with light provides a possible mechanism for producing cooperative behavior between swarms of semiautonomous nanorobots.

  20. Cationic gemini surfactant-assisted synthesis of hollow Au nanostructures by stepwise reductions.

    Science.gov (United States)

    Wang, Wentao; Han, Yuchun; Tian, Maozhang; Fan, Yaxun; Tang, Yongqiang; Gao, Mingyuan; Wang, Yilin

    2013-06-26

    A novel synthetic approach was developed for creating versatile hollow Au nanostructures by stepwise reductions of Au(III) upon the use of cationic gemini surfactant hexamethylene-1,6-bis(dodecyl dimethylammonium bromide) (C12C6C12Br2) as a template agent. It was observed that the Au(I) ions obtained from the reduction of Au(III) by ascorbic acid can assist the gemini surfactant to form vesicles, capsule-like, and tube-like aggregates that subsequently act as soft templates for hollow Au nanostructures upon further reduction of Au(I) to Au(0) by NaBH4. It was demonstrated that the combination of C12C6C12Br2 and Au(I) plays a key role in regulating the structure of the hollow precursors not only because C12C6C12Br2 has a stronger aggregation ability in comparison with its single chain counterpart but also because the electrostatic repulsion between head groups of C12C6C12Br2 is greatly weakened after Au(III) is converted to Au(I), which is in favor of the construction of vesicles, capsule-like, and tube-like aggregates. Compared with solid Au nanospheres, the resultant hollow nanostructures exhibit enhanced electrocatalytic activities in methanol oxidation, following the order of elongated nanocapsule > nanocapsule > nanosphere. Benefiting from balanced interactions between the gemini surfactant and Au(I), this soft-template method may present a facile and versatile approach for the controlled synthesis of Au nanostructures potentially useful for fuel cells and other Au nanodevices.

  1. Hydrogen accumulation in nanostructured as compared to the coarse-grained tungsten

    International Nuclear Information System (INIS)

    Gonzalez-Arrabal, R.; Panizo-Laiz, M.; Gordillo, N.; Tejado, E.; Munnik, F.; Rivera, A.; Perlado, J.M.

    2014-01-01

    Highlights: • Study of the hydrogen behaviour in nanostructured as compare to coarse grained tungsten samples. • Comparison between single (H), sequentially (C plus H) and simultaneously (C and H) implanted samples. • Study of the stability of the nanostructures after implantation at different temperatures. • Implantation energies for H and C above the displacement damage threshold. • Study of the hydrogen behaviour as a function of the implantation temperature. - Abstract: We report on the influence of sample microstructure and of irradiation conditions on the H behaviour in Tungsten (W). For this purpose, commercial coarse grained (CGW) and nanostructured W (NW) samples were implanted with (i) H at room temperature (RT), (ii) sequentially with C and H at RT, and (iii) simultaneously (co-implanted) with C and H at RT. To study the possible effect of implantation temperature on H behaviour, a CGW sample and a NW sample were sequentially implanted with C at RT and with H at 673 K. The H and C implantation fluence was 5 × 10 20 m −2 and the implantation energies were 160 keV for H and 650 keV for C which are above the displacement damage threshold. Scanning electron microscopy images show that nanostructured samples consist of columns with an average diameter of about 100 nm. These nanocolumns are stable under the studied implantations conditions. Moreover, surface modification is absent in all studied samples. X-ray diffraction data illustrate that all samples are mono-phase (α-W phase) and that none of the implantations led to the appearance of secondary phases. Resonant nuclear reaction analysis data show that the H retention in NW samples is larger than in CGW and that synergistic effect has a significant influence on the H retention in CGW samples but not in NW samples

  2. Sensing properties of pristine boron nitride nanostructures towards alkaloids: A first principles dispersion corrected study

    Science.gov (United States)

    Roondhe, Basant; Dabhi, Shweta D.; Jha, Prafulla K.

    2018-05-01

    To understand the underlying physics behind the interaction of biomolecules with the nanomaterials to use them practically as bio-nanomaterials is very crucial. A first principles calculation under the frame work of density functional theory is executed to investigate the electronic structures and binding properties of alkaloids (Caffeine and Nicotine) over single walled boron nitride nanotube (BNNT) and boron nitride nanoribbon (BNNR) to determine their suitability towards filtration or sensing of these molecules. We have also used GGA-PBE scheme with the inclusion of Van der Waals (vdW) interaction based on DFT-D2. Increase in the accuracy by incorporating the dispersion correction in the calculation is observed for the long range Van der Waals interaction. Binding energy range of BNNT and BNNR with both alkaloids have been found to be -0.35 to -0.76 eV and -0.45 to -0.91 eV respectively which together with the binding distance shows physisorption binding of these molecules to the both nanostructures. The transfer of charge between the BN nanostructures and the adsorbed molecule has also been analysed by using Lowdin charge analysis. The sensitivity of both nanostructures BNNT and BNNR towards both alkaloids is observed through electronic structure calculations, density of states and quantum conductance. The binding of both alkaloids with BNNR is stronger. The analysis of the calculated properties suggests absence of covalent interaction between the considered species (BNNT/BNNR) and alkaloids. The study may be useful in designing the boron nitride nanostructure based sensing device for alkaloids.

  3. Patterning protein complexes on DNA nanostructures using a GFP nanobody.

    Science.gov (United States)

    Sommese, R F; Hariadi, R F; Kim, K; Liu, M; Tyska, M J; Sivaramakrishnan, S

    2016-11-01

    DNA nanostructures have become an important and powerful tool for studying protein function over the last 5 years. One of the challenges, though, has been the development of universal methods for patterning protein complexes on DNA nanostructures. Herein, we present a new approach for labeling DNA nanostructures by functionalizing them with a GFP nanobody. We demonstrate the ability to precisely control protein attachment via our nanobody linker using two enzymatic model systems, namely adenylyl cyclase activity and myosin motility. Finally, we test the power of this attachment method by patterning unpurified, endogenously expressed Arp2/3 protein complex from cell lysate. By bridging DNA nanostructures with a fluorescent protein ubiquitous throughout cell and developmental biology and protein biochemistry, this approach significantly streamlines the application of DNA nanostructures as a programmable scaffold in biological studies. © 2016 The Protein Society.

  4. Matrix-assisted energy conversion in nanostructured piezoelectric arrays

    Science.gov (United States)

    Sirbuly, Donald J.; Wang, Xianying; Wang, Yinmin

    2013-01-01

    A nanoconverter is capable of directly generating electricity through a nanostructure embedded in a polymer layer experiencing differential thermal expansion in a stress transfer zone. High surface-to-volume ratio semiconductor nanowires or nanotubes (such as ZnO, silicon, carbon, etc.) are grown either aligned or substantially vertically aligned on a substrate. The resulting nanoforest is then embedded with the polymer layer, which transfers stress to the nanostructures in the stress transfer zone, thereby creating a nanostructure voltage output due to the piezoelectric effect acting on the nanostructure. Electrodes attached at both ends of the nanostructures generate output power at densities of .about.20 nW/cm.sup.2 with heating temperatures of .about.65.degree. C. Nanoconverters arrayed in a series parallel arrangement may be constructed in planar, stacked, or rolled arrays to supply power to nano- and micro-devices without use of external batteries.

  5. Differential Geometry Applied to Rings and Möbius Nanostructures

    DEFF Research Database (Denmark)

    Lassen, Benny; Willatzen, Morten; Gravesen, Jens

    2014-01-01

    Nanostructure shape effects have become a topic of increasing interest due to advancements in fabrication technology. In order to pursue novel physics and better devices by tailoring the shape and size of nanostructures, effective analytical and computational tools are indispensable. In this chap......Nanostructure shape effects have become a topic of increasing interest due to advancements in fabrication technology. In order to pursue novel physics and better devices by tailoring the shape and size of nanostructures, effective analytical and computational tools are indispensable....... In this chapter, we present analytical and computational differential geometry methods to examine particle quantum eigenstates and eigenenergies in curved and strained nanostructures. Example studies are carried out for a set of ring structures with different radii and it is shown that eigenstate and eigenenergy...

  6. Laser-assisted nanostructuring of Tungsten in liquid environment

    Energy Technology Data Exchange (ETDEWEB)

    Barmina, E.V., E-mail: barminaev@gmail.com [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); Stratakis, E. [Institute of Electronic Structure and Laser, Foundation for Research and Technology, Hellas (IESL-FORTH), P.O. Box 1527, Heraklion 711 10 (Greece); Materials Science and Technology Department, University of Crete, Heraklion 710 03 (Greece); Barberoglou, M. [Institute of Electronic Structure and Laser, Foundation for Research and Technology, Hellas (IESL-FORTH), P.O. Box 1527, Heraklion 711 10 (Greece); Physics Department, University of Crete, Heraklion 714 09 (Greece); Stolyarov, V.N.; Stolyarov, I.N. [Roentgenprom, 35 Lenin str., Protvino, 1442281 Moscow region (Russian Federation); Fotakis, C. [Institute of Electronic Structure and Laser, Foundation for Research and Technology, Hellas (IESL-FORTH), P.O. Box 1527, Heraklion 711 10 (Greece); Physics Department, University of Crete, Heraklion 714 09 (Greece); Shafeev, G.A. [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation)

    2012-05-15

    Formation of surface nanostructures on Tungsten target immersed into liquids is experimentally studied under its exposure to femtosecond laser pulses with different durations. In particular, nanotexturing of Tungsten upon its exposure to delayed femtosecond pulses is investigated. Two different types of morphological features are observed, namely periodic ripples and nanostructures. Field emission scanning electron microscopy shows that the density of nanostructures as well as their morphology depends on the time delay between pulses and reaches its maximum at 1 ps delay. Thermionic emission of nano-structured W cathode is investigated. The work function of nanostructured W surface is measured to be 0.3 eV lower than that of the pristine surface.

  7. Structural DNA Nanotechnology: Artificial Nanostructures for Biomedical Research.

    Science.gov (United States)

    Ke, Yonggang; Castro, Carlos; Choi, Jong Hyun

    2018-04-04

    Structural DNA nanotechnology utilizes synthetic or biologic DNA as designer molecules for the self-assembly of artificial nanostructures. The field is founded upon the specific interactions between DNA molecules, known as Watson-Crick base pairing. After decades of active pursuit, DNA has demonstrated unprecedented versatility in constructing artificial nanostructures with significant complexity and programmability. The nanostructures could be either static, with well-controlled physicochemical properties, or dynamic, with the ability to reconfigure upon external stimuli. Researchers have devoted considerable effort to exploring the usability of DNA nanostructures in biomedical research. We review the basic design methods for fabricating both static and dynamic DNA nanostructures, along with their biomedical applications in fields such as biosensing, bioimaging, and drug delivery. Expected final online publication date for the Annual Review of Biomedical Engineering Volume 20 is June 4, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  8. Diverse Near-Infrared Resonant Gold Nanostructures for Biomedical Applications

    KAUST Repository

    Huang, Jianfeng

    2015-12-08

    The ability of near-infrared (NIR) light to penetrate tissues deeply and to target malignant sites with high specificity via precise temporal and spatial control of light illumination makes it useful for diagnosing and treating diseases. Owing to their unique biocompatibility, surface chemistry and optical properties, gold nanostructures offer advantages as in vivo NIR photosensitizers. This chapter describes the recent progress in the varied use of NIR-resonant gold nanostructures for NIR-light-mediated diagnostic and therapeutic applications. We begin by describing the unique biological, chemical and physical properties of gold nanostructures that make them excellent candidates for biomedical applications. From here, we make an account of the basic principles involved in the diagnostic and therapeutic applications where gold nanostructures have set foot. Finally, we review recent developments in the fabrication and use of diverse NIR-resonant gold nanostructures for cancer imaging and cancer therapy.

  9. Nanostructured carbon films with oriented graphitic planes

    International Nuclear Information System (INIS)

    Teo, E. H. T.; Kalish, R.; Kulik, J.; Kauffmann, Y.; Lifshitz, Y.

    2011-01-01

    Nanostructured carbon films with oriented graphitic planes can be deposited by applying energetic carbon bombardment. The present work shows the possibility of structuring graphitic planes perpendicular to the substrate in following two distinct ways: (i) applying sufficiently large carbon energies for deposition at room temperature (E>10 keV), (ii) utilizing much lower energies for deposition at elevated substrate temperatures (T>200 deg. C). High resolution transmission electron microscopy is used to probe the graphitic planes. The alignment achieved at elevated temperatures does not depend on the deposition angle. The data provides insight into the mechanisms leading to the growth of oriented graphitic planes under different conditions.

  10. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  11. Nanostructured Electrode Materials for Electrochemical Capacitor Applications.

    Science.gov (United States)

    Choi, Hojin; Yoon, Hyeonseok

    2015-06-02

    The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  12. Radiation damage in nanostructured metallic films

    Science.gov (United States)

    Yu, Kaiyuan

    High energy neutron and charged particle radiation cause microstructural and mechanical degradation in structural metals and alloys, such as phase segregation, void swelling, embrittlement and creep. Radiation induced damages typically limit nuclear materials to a lifetime of about 40 years. Next generation nuclear reactors require materials that can sustain over 60 - 80 years. Therefore it is of great significance to explore new materials with better radiation resistance, to design metals with favorable microstructures and to investigate their response to radiation. The goals of this thesis are to study the radiation responses of several nanostructured metallic thin film systems, including Ag/Ni multilayers, nanotwinned Ag and nanocrystalline Fe. Such systems obtain high volume fraction of boundaries, which are considered sinks to radiation induced defects. From the viewpoint of nanomechanics, it is of interest to investigate the plastic deformation mechanisms of nanostructured films, which typically show strong size dependence. By controlling the feature size (layer thickness, twin spacing and grain size), it is applicable to picture a deformation mechanism map which also provides prerequisite information for subsequent radiation hardening study. And from the viewpoint of radiation effects, it is of interest to explore the fundamentals of radiation response, to examine the microstructural and mechanical variations of irradiated nanometals and to enrich the design database. More importantly, with the assistance of in situ techniques, it is appealing to examine the defect generation, evolution, annihilation, absorption and interaction with internal interfaces (layer interfaces, twin boundaries and grain boundaries). Moreover, well-designed nanostructures can also verify the speculation that radiation induced defect density and hardening show clear size dependence. The focus of this thesis lies in the radiation response of Ag/Ni multilayers and nanotwinned Ag

  13. Atomic layer deposition of nanostructured materials

    CERN Document Server

    Pinna, Nicola

    2012-01-01

    Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (du

  14. Annealing relaxation of ultrasmall gold nanostructures

    Science.gov (United States)

    Chaban, Vitaly

    2015-01-01

    Except serving as an excellent gift on proper occasions, gold finds applications in life sciences, particularly in diagnostics and therapeutics. These applications were made possible by gold nanoparticles, which differ drastically from macroscopic gold. Versatile surface chemistry of gold nanoparticles allows coating with small molecules, polymers, biological recognition molecules. Theoretical investigation of nanoscale gold is not trivial, because of numerous metastable states in these systems. Unlike elsewhere, this work obtains equilibrium structures using annealing simulations within the recently introduced PM7-MD method. Geometries of the ultrasmall gold nanostructures with chalcogen coverage are described at finite temperature, for the first time.

  15. Applications of oligomers for nanostructured conducting polymers.

    Science.gov (United States)

    Wang, Yue; Tran, Henry D; Kaner, Richard B

    2011-01-03

    This Feature Article provides an overview of the distinctive nanostructures that aniline oligomers form and the applications of these oligomers for shaping the nanoscale morphologies and chirality of conducting polymers. We focus on the synthetic methods for achieving such goals and highlight the underlying mechanisms. The clear advantages of each method and their possible drawbacks are discussed. Assembly and applications of these novel organic (semi)conducting nanomaterials are also outlined. We conclude this article with our perspective on the main challenges, new opportunities, and future directions for this nascent yet vibrant field of research. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Quantum interference effects in nanostructured Au

    CERN Document Server

    Pratumpong, P; Evans, S D; Johnson, S; Howson, M A

    2002-01-01

    We present results on the magnetoresistance and temperature dependence of the resistivity for nanostructured Au produced by chemical means. The magnetoresistance was typical of highly disordered metals exhibiting quantum interference effects. We fitted the data and were able to determine the spin-orbit scattering relaxation time to be 10 sup - sup 1 sup 2 s and we found the inelastic scattering time at 10 K to be 10 sup - sup 1 sup 1 s. The inelastic scattering rate varied as T sup 3 between 4 and 20 K, which is typical for electron-phonon scattering in disordered metals.

  17. Quantum theory of plasmons in nanostructures

    DEFF Research Database (Denmark)

    Winther, Kirsten Trøstrup

    ripples in a pond where the water represents a sea of free electrons. Plasmons on metal surfaces and in nanostructured materials, such as metal nanoparticles and atomically thin two-dimensional materials, have several technological applications due to their ability to confine light on nanoscale......, also van der Waals heterostructures (vdWh), which are stacks of different twodimensional materials, are considered. A new multi-scale approach for calculating the dielectric-function of vdWh, which extends ab initio accuracy to the description of hundreds of atomic layers, is presented. Also, one...

  18. Nanostructured materials, production and application in construction

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2014-12-01

    Full Text Available The paper considers characteristics of water-soluble high module silicate systems: based on polysilicates of alkali element called liquid glasses and the chains of their transformations from the lowest oligomers into the highest ones with further formation colloid solutions – silica sol. The authors describe the potentialities of the use of such systems as binders or modifying additives to produce different nanostructured silicate polymer concretes. There are examples of prospective application of liquid glass and water solutions of high module silicates in industrial areas and construction. Quantum-chemical calculations of the structure and properties of tetraphenylarsonium are given and heterogeneity of its functional groups is shown.

  19. Nanostructured diamond coatings for orthopaedic applications

    Science.gov (United States)

    CATLEDGE, S.A.; THOMAS, V.; VOHRA, Y.K.

    2013-01-01

    With increasing numbers of orthopaedic devices being implanted, greater emphasis is being placed on ceramic coating technology to reduce friction and wear in mating total joint replacement components, in order to improve implant function and increase device lifespan. In this chapter, we consider ultra-hard carbon coatings, with emphasis on nanostructured diamond, as alternative bearing surfaces for metallic components. Such coatings have great potential for use in biomedical implants as a result of their extreme hardness, wear resistance, low friction and biocompatibility. These ultra-hard carbon coatings can be deposited by several techniques resulting in a wide variety of structures and properties. PMID:25285213

  20. Raman Spectroscopy and its Application in Nanostructures

    CERN Document Server

    Zhang, Shu-Lin

    2012-01-01

    Raman Spectroscopy and its Application in Nanostructures is an original and timely contribution to a very active area of physics and materials science research. This book presents the theoretical and experimental phenomena of Raman spectroscopy, with specialized discussions on the physical fundamentals, new developments and main features in low-dimensional systems of Raman spectroscopy. In recent years physicists, materials scientists and chemists have devoted increasing attention to low-dimensional systems and as Raman spectroscopy can be used to study and analyse such materials as carbon nan