Nanotechnology (NANOTECHNOLOGY)

Publications in this journal

• Article: A new bottom-up methodology to produce silicon layers with a closed porosity nanostructure and reduced refractive index

  Vanda Godinho, Jaime Caballero-Hernandez, Damien Jamon, Teresa Cristina Rojas, Roland Shierholz, Javier Garcia-Lopez, Javier Ferrer Francisco, Asuncion Fernandez
  Nanotechnology 06/2013;
• Article: Direct patterning of high density sub-15 nm gold dot arrays using ultrahigh contrast electron beam lithography process on positive tone resist

  Landobasa Y. M. Tobing, Liliana Tjahjana, Dao Hua ZHang
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  ABSTRACT: Ultrahigh density nanostructure arrays with controlled size and position have promised a variety of potential applications. However, their practical realization is often hindered by the amount of resources required for large-scale fabrication. Using an ultrahigh contrast electron beam lithography process, we show ultrahigh resolution and high aspect ratio patterning capability which can be done at an exposure dose lower than 100 μC cm−2. In particular, the high aspect ratio of dot arrays on 110 nm thick resist is confirmed by a standard lift-off process of 20 nm thick gold nanodots at sub-15 nm feature size and 40 nm pitch. The smallest gold nanodot size from our experiment is ~11 nm.
  Nanotechnology 02/2013; 24(7):075303.
• Article: Track membranes with embedded semiconductor nanocrystals: structural and optical examinations

  Orlova A.O, Gromova Y.A, Savelyeva A.V, Maslov V.G, Artemyev M.V, Prudnikau A, Fedorov A.V, Baranov A.V
  Nanotechnology 02/2013; 22(45):455201.
• Article: Lab-in-a-drop: controlled self-assembly of CdSe/ZnS quantum dots and quantum rods into polycrystalline nanostructures with desired optical properties

  Sukhanova A, Volkov Y, Rogach A.L, Baranov A.V, Susha A.S, Klinov D, Oleinikov V, Cohen J.H.M, Nabiev I
  Nanotechnology 02/2013; 18(18):185602.
• Article: DNA-assisted formation of quasi-nanowires from fluorescent CdSe/ZnS nanocrystals

  Stsiapura V, Sukhanova A, Baranov A, Artemyev M, Kulakovich O, Oleinikov V, Pluot M, Cohen J.H.M, Nabiev I
  Nanotechnology 02/2013; 17(2):581.
• Article: Self-assembly of charged microclusters of CdSe/ZnS core/shell nanodots and nanorods into hierarchically ordered colloidal arrays

  Sukhanova A, Baranov A.V, Klinov D, Oleinikov V, Berwik K, Cohen J.H.M, Pluot M, Nabiev I
  Nanotechnology 02/2013; 17(16):4223.
• Article: The role of the gas species on the formation of carbon nanotubes during thermal chemical vapour deposition.

  Fumitaka Ohashi, Guan Yow Chen, Vlad Stolojan, S Ravi P Silva
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  ABSTRACT: In this paper, we investigate the several roles that hydrogen plays in the catalytic growth of carbon nanotubes from the point of view of gas species, catalyst activation and subsequent interaction with the carbon nanotubes. Carbon nanotubes and nanofibres were grown by thermal chemical vapour deposition, using methane and a mixture of hydrogen and helium, for a range of growth temperatures and pre-treatment procedures. Long, straight carbon nanotubes were obtained at 900 °C, and although the growth yield increases with the growth temperature, the growth shifts from nanotubes to nanofibres. By introducing a helium purge as part of the pre-treatment procedure, we change the gas chemistry by altering the hydrogen concentration in the initial reaction stage. This simple change in the process resulted in a clear difference in the yield and the structure of the carbon nanofibres produced. We find that the hydrogen concentration in the initial reaction stage significantly affects the morphology of carbon fibres. Although hydrogen keeps the catalyst activated and increases the yield, it prevents the formation of graphitic nanotubes.
  Nanotechnology 02/2013; 19(44):445605.
• Article: Probing the energy barriers and magnetization reversal processes of nanoperforated membrane based percolated media

  V Neu, C Schulze, M Faustini, J Lee, D Makarov, D Suess, S-K Kim, D Grosso, L Schultz, M Albrecht
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  ABSTRACT: Magnetization reversal processes in Co/Pt multilayers prepared on nanoperforated templates are probed by magnetization relaxation measurements. The signature of pinning controlled domain wall movement as expected for percolated media is identified. This contrasts with the nucleation-type reversal mechanism of a Co/Pt reference film prepared on a smooth substrate. A zero field energy barrier of 93kBT is determined by fluctuation field measurements and is elucidated by micromagnetic calculations using the nudged elastic band method. This value is sufficiently large to qualify the material as a promising percolated medium.
  Nanotechnology 01/2013; 24:145702.
• Article: Nitrogen, boron doped and undoped multiwalled Carbon nanotubes polymer composite in WORM memory device

  • M. A. Mamo, A. O. Sustaita, Z. Taitana, N. J. Coville, I. A. Hümmelgen
  Nanotechnology 01/2013;
• Article: Strategies for specifically direct metal functionalization to the inner or outer surface of protein nanotubes: the case of silver nanowires

  Liliana Carreño-Fuentes, Jorge A. Ascencio, Ariosto Medina, Sergio A. Águila, Laura A. Palomares, Octavio T. Ramírez
  Nanotechnology 01/2013;
• Article: Hierarchical weeping willow nano-tree growth and effect of branching on dye-sensitized solar cell efficiency

  Indria Herman, Junyeob Yeo, Sukjoon Hong, Daeho Lee, Koo Hyun Nam, Jun-ho Choi, Won-hwa Hong, Dongjin Lee, Costas P Grigoropoulos, Seung Hwan Ko
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  ABSTRACT: In this paper we have demonstrated the simple, low cost, low temperature, hydrothermal growth of weeping willow ZnO nano-trees with very long branches to realize high efficiency dye-sensitized solar cells (DSSCs). We also discuss the effects of branching on solar cell efficiency. By introducing branched growth on the backbone ZnO nanowires (NWs), the short circuit current density and the overall light conversion efficiency of the branched ZnO NW DSSCs increased to almost four times that for vertically grown ZnO NWs. The efficiency increase is attributed to the increase in surface area for higher dye loading and light harvesting and also to reduced charge recombination through direct conduction along the crystalline ZnO branches. As the length of the branches increased, the branches became flaccid and the increase in solar cell efficiency slowed down because the effective surface area increase was hindered by branch bundling during the drying process and subsequent decrease in the dye loading.
  Nanotechnology 04/2012; 23(19):194005.
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  Available from: mnelab.com

  Article: The application of graphene as electrodes in electrical and optical devices

  Gunho Jo, Minhyeok Choe, Sangchul Lee, Woojin Park, Yung Ho Kahng, Takhee Lee
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  ABSTRACT: Graphene is a promising next-generation conducting material with the potential to replace traditional electrode materials such as indium tin oxide in electrical and optical devices. It combines several advantageous characteristics including low sheet resistance, high optical transparency and excellent mechanical properties. Recent research has coincided with increased interest in the application of graphene as an electrode material in transistors, light-emitting diodes, solar cells and flexible devices. However, for more practical applications, the performance of devices should be further improved by the engineering of graphene films, such as through their synthesis, transfer and doping. This article reviews several applications of graphene films as electrodes in electrical and optical devices and discusses the essential requirements for applications of graphene films as electrodes.
  Nanotechnology 02/2012; 23(11):112001.
• Article: Magnetization dynamics, throughput and energy dissipation in a universal multiferroic nanomagnetic logic gate with fan-in and fan-out

  Fashami, Jayasimha Atulasimha, Supriyo Bandyopadhyay
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  ABSTRACT: The switching dynamics of a multiferroic nanomagnetic NAND gate with fan-in/fan-out is simulated by solving the Landau–Lifshitz–Gilbert (LLG) equation while neglecting thermal fluctuation effects. The gate and logic wires are implemented with dipole-coupled two-phase (magnetostrictive/piezoelectric) multiferroic elements that are clocked with electrostatic potentials of ~50 mV applied to the piezoelectric layer generating 10.1 MPa stress in the magnetostrictive layers for switching. We show that a pipeline bit throughput rate of ~0.5 GHz is achievable with proper magnet layout and sinusoidal four-phase clocking. The gate operation is completed in 2 ns with a latency of 4 ns. The total (internal + external) energy dissipated for a single gate operation at this throughput rate is found to be only ~500 kT in the gate and ~1250 kT in the 12-magnet array comprising two input and two output wires for fan-in and fan-out. This makes it respectively three and five orders of magnitude more energy-efficient than complementary-metal–oxide–semiconductor-transistor (CMOS)-based and spin-transfer-torque-driven nanomagnet-based NAND gates. Finally, we show that the dissipation in the external clocking circuit can always be reduced asymptotically to zero using increasingly slow adiabatic clocking, such as by designing the RC time constant to be three orders of magnitude smaller than the clocking period. However, the internal dissipation in the device must remain and cannot be eliminated if we want to perform fault-tolerant classical computing.
  Nanotechnology 02/2012; 23(10):105201.