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Shu Ping Lau - One of the best experts on this subject based on the ideXlab platform.
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Ferromagnetic anisotropy of carbon-doped ZnO Nanoneedles fabricated by ion beam technique
Applied Surface Science, 2012Co-Authors: C. S. Wei, Shu Ping Lau, Masaki Tanemura, M. Subramanian, Y. AkaikeAbstract:Abstract Carbon-doped ZnO (ZnO:C) Nanoneedles were fabricated using ion beam irradiation with a simultaneous supply of carbon at room temperature. The structure and the magnetic properties of the ZnO:C Nanoneedles were investigated. Hysteresis loops and zero-field cooling (ZFC) and field cooling (FC) curves demonstrated the ferromagnetic properties of the ZnO:C Nanoneedles. The Curie temperature of the ZnO:C is above 330 K. The ferromagnetic anisotropy with an easy axis perpendicular to the shape axis of the ZnO:C Nanoneedles was observed due to the dipole–dipole magnetic interaction amongst Nanoneedles.
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Ferromagnetic carbon-doped ZnO Nanoneedles
2010 3rd International Nanoelectronics Conference (INEC), 2010Co-Authors: Shu Ping Lau, Tun Seng Herng, Changsong Wei, Masaki TanemuraAbstract:Carbon doped ZnO (ZnO∶C) Nanoneedles exhibiting Curie temperature above room temperature were fabricated using ion beam technique. The structural and magnetic properties of the ZnO∶C Nanoneedles were studied. The magnetic moment of the ZnO∶C Nanoneedles was found to be around 0.7 µ B per carbon atom. The ZnO∶C Nanoneedles could be a promising intrinsic diluted magnetic semiconductor.
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stable ferromagnetism in p type carbon doped zno Nanoneedles
Applied Physics Letters, 2009Co-Authors: Tun Seng Herng, Shu Ping Lau, Masaki Tanemura, Changsong Wei, Lin Wang, Bangchuan Zhao, Y. AkaikeAbstract:The authors report the synthesis and magnetic properties of carbon-doped ZnO (ZnO:C) Nanoneedles. A saturated magnetic moment of 2.16 emu/cm3 was found in the ZnO:C Nanoneedles. The samples showed anomalous Hall effect and p-type conduction with a hole concentration of 1.8×1018 cm−3. The ferromagnetism in the ZnO:C Nanoneedles could be attributed to C substitution on the O site which introduces hole, so the p-p interaction leads to the strong spin interaction between the C atoms and carriers. It was found that the ferromagnetism and p-type conduction in the ZnO:C Nanoneedles were stable in ambient air over a period of 1 year and annealing temperature of up to 100 °C.
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Stable ferromagnetism in p-type carbon-doped ZnO Nanoneedles
Applied Physics Letters, 2009Co-Authors: Tun Seng Herng, Shu Ping Lau, Masaki Tanemura, Changsong Wei, Lin Wang, Bangchuan Zhao, Y. AkaikeAbstract:The authors report the synthesis and magnetic properties of carbon-doped ZnO (ZnO:C) Nanoneedles. A saturated magnetic moment of 2.16 emu/cm³ was found in the ZnO:C Nanoneedles. The samples showed anomalous Hall effect and p-type conduction with a hole concentration of 1.8 X 10¹⁸cm⁻³. The ferromagnetism in the ZnO:C Nanoneedles could be attributed to C substitution on the O site which introduces hole, so the p-p interaction leads to the strong spin interaction between the C atoms and carriers. It was found that the ferromagnetism and p-type conduction in the ZnO:C Nanoneedles were stable in ambient air over a period of 1 year and annealing temperature of up to 100 °C.Department of Applied PhysicsAuthor name used in this publication: C. S. We
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magnetic anisotropy in the ferromagnetic cu doped zno Nanoneedles
Applied Physics Letters, 2007Co-Authors: Tun Seng Herng, Shu Ping Lau, Hui Ying Yang, Masaki Tanemura, Lin Wang, J S ChenAbstract:Copper-doped ZnO (ZnO:Cu) Nanoneedles exhibiting room-temperature ferromagnetism were fabricated by an ion beam technique using Cu plate and ZnO film. A saturated magnetization moment of 0.698emu∕cm3 was found in the Nanoneedles when a field of 10kOe was applied perpendicular to the substrate, which was 15% larger than the field applied parallel to the substrate. The magnetic ordering of the Nanoneedles was enhanced significantly to 0.968emu∕cm3 after annealing of 400°C for 20min. However, the magnetic anisotropy at high field is vanished but an “easy plane” ferromagnetism becomes apparent at low field region. The possible mechanisms of the magnetic ordering and anisotropy in the ZnO:Cu Nanoneedles are discussed.
Masaki Tanemura - One of the best experts on this subject based on the ideXlab platform.
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Ferromagnetic anisotropy of carbon-doped ZnO Nanoneedles fabricated by ion beam technique
Applied Surface Science, 2012Co-Authors: C. S. Wei, Shu Ping Lau, Masaki Tanemura, M. Subramanian, Y. AkaikeAbstract:Abstract Carbon-doped ZnO (ZnO:C) Nanoneedles were fabricated using ion beam irradiation with a simultaneous supply of carbon at room temperature. The structure and the magnetic properties of the ZnO:C Nanoneedles were investigated. Hysteresis loops and zero-field cooling (ZFC) and field cooling (FC) curves demonstrated the ferromagnetic properties of the ZnO:C Nanoneedles. The Curie temperature of the ZnO:C is above 330 K. The ferromagnetic anisotropy with an easy axis perpendicular to the shape axis of the ZnO:C Nanoneedles was observed due to the dipole–dipole magnetic interaction amongst Nanoneedles.
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Ferromagnetic carbon-doped ZnO Nanoneedles
2010 3rd International Nanoelectronics Conference (INEC), 2010Co-Authors: Shu Ping Lau, Tun Seng Herng, Changsong Wei, Masaki TanemuraAbstract:Carbon doped ZnO (ZnO∶C) Nanoneedles exhibiting Curie temperature above room temperature were fabricated using ion beam technique. The structural and magnetic properties of the ZnO∶C Nanoneedles were studied. The magnetic moment of the ZnO∶C Nanoneedles was found to be around 0.7 µ B per carbon atom. The ZnO∶C Nanoneedles could be a promising intrinsic diluted magnetic semiconductor.
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stable ferromagnetism in p type carbon doped zno Nanoneedles
Applied Physics Letters, 2009Co-Authors: Tun Seng Herng, Shu Ping Lau, Masaki Tanemura, Changsong Wei, Lin Wang, Bangchuan Zhao, Y. AkaikeAbstract:The authors report the synthesis and magnetic properties of carbon-doped ZnO (ZnO:C) Nanoneedles. A saturated magnetic moment of 2.16 emu/cm3 was found in the ZnO:C Nanoneedles. The samples showed anomalous Hall effect and p-type conduction with a hole concentration of 1.8×1018 cm−3. The ferromagnetism in the ZnO:C Nanoneedles could be attributed to C substitution on the O site which introduces hole, so the p-p interaction leads to the strong spin interaction between the C atoms and carriers. It was found that the ferromagnetism and p-type conduction in the ZnO:C Nanoneedles were stable in ambient air over a period of 1 year and annealing temperature of up to 100 °C.
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Stable ferromagnetism in p-type carbon-doped ZnO Nanoneedles
Applied Physics Letters, 2009Co-Authors: Tun Seng Herng, Shu Ping Lau, Masaki Tanemura, Changsong Wei, Lin Wang, Bangchuan Zhao, Y. AkaikeAbstract:The authors report the synthesis and magnetic properties of carbon-doped ZnO (ZnO:C) Nanoneedles. A saturated magnetic moment of 2.16 emu/cm³ was found in the ZnO:C Nanoneedles. The samples showed anomalous Hall effect and p-type conduction with a hole concentration of 1.8 X 10¹⁸cm⁻³. The ferromagnetism in the ZnO:C Nanoneedles could be attributed to C substitution on the O site which introduces hole, so the p-p interaction leads to the strong spin interaction between the C atoms and carriers. It was found that the ferromagnetism and p-type conduction in the ZnO:C Nanoneedles were stable in ambient air over a period of 1 year and annealing temperature of up to 100 °C.Department of Applied PhysicsAuthor name used in this publication: C. S. We
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magnetic anisotropy in the ferromagnetic cu doped zno Nanoneedles
Applied Physics Letters, 2007Co-Authors: Tun Seng Herng, Shu Ping Lau, Hui Ying Yang, Masaki Tanemura, Lin Wang, J S ChenAbstract:Copper-doped ZnO (ZnO:Cu) Nanoneedles exhibiting room-temperature ferromagnetism were fabricated by an ion beam technique using Cu plate and ZnO film. A saturated magnetization moment of 0.698emu∕cm3 was found in the Nanoneedles when a field of 10kOe was applied perpendicular to the substrate, which was 15% larger than the field applied parallel to the substrate. The magnetic ordering of the Nanoneedles was enhanced significantly to 0.968emu∕cm3 after annealing of 400°C for 20min. However, the magnetic anisotropy at high field is vanished but an “easy plane” ferromagnetism becomes apparent at low field region. The possible mechanisms of the magnetic ordering and anisotropy in the ZnO:Cu Nanoneedles are discussed.
Gaoquan Shi - One of the best experts on this subject based on the ideXlab platform.
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production and characterization of stable superhydrophobic surfaces based on copper hydroxide Nanoneedles mimicking the legs of water striders
Journal of Physical Chemistry B, 2006Co-Authors: Xufeng Wu And, Gaoquan ShiAbstract:The present work reports a simple and economic route for production and characterization of stable superhydrophobic surfaces from thin copper layers coated on arbitrary solid substrates. The thin copper layer was anodized in a 2 M aqueous solution of potassium hydroxide to form a thin film of copper hydroxide Nanoneedles; then the film was reacted with n-dodecanethiol to form a thermally stable Cu(SC12H25)2 superhydrophobic coating. The contact angle of the modified nanoneedle surface was higher than 150°, and its tilt angle was smaller than 2°. Furthermore, the surface fabricated on copper foil kept its superhydrophobic property after heating at 160 °C in air for over 42 h. This technique has also been applied for fabrication of copper wire with superhydrophobic submicrofiber coating to mimic water strider legs. The maximal supporting force of the superhydrophobic copper column has also been investigated in comparison to real water striders.
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Copper hydroxide nanoneedle and nanotube arrays fabricated by anodization of copper
Journal of Physical Chemistry B, 2005Co-Authors: Xufeng Wu, Feng'en Chen, Jiaxin Zhang, Hua Bai, Gaoquan ShiAbstract:Cu(OH)2 nanoneedle and nanotube arrays were electrochemically synthesized by anodization of a copper foil in an aqueous solution of KOH. The Nanoneedles and nanotubes were constructed from nanosheets of Cu(OH)2. Controlling the electrochemical conditions can qualitatively modulate the lengths, amounts, and shapes of Cu(OH)2 nanostructures. The composition of as-prepared Cu(OH)2 nanostructures has been confirmed by X-ray diffraction and select-area electron diffraction. The influences of the KOH concentration of the aqueous electrolyte, the reaction temperature, and current density on the morphology of Cu(OH)2 nanostructures were investigated, and the formation mechanism of the nanostructures is discussed. Furthermore, Cu(OH)2 Nanoneedles can be successfully transformed to CuO Nanoneedles with little morphology change by heating. This work developed a simple, clean, and effective route for fabrication of large area Cu(OH)2 or CuO nanostructured films.
Tewodros Asefa - One of the best experts on this subject based on the ideXlab platform.
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edge plane rich nitrogen doped carbon Nanoneedles and efficient metal free electrocatalysts
Angewandte Chemie, 2012Co-Authors: Rafael Silva, Jafar F Alsharab, Tewodros AsefaAbstract:CNN news: N-doped carbon Nanoneedles (CNNs) are synthesized by self-assembling core-shell nanostructures and nanoreactors around cellulose Nanoneedles, and subsequent graphitization. The resulting graphitic Nanoneedles (see picture) have well-organized graphitic multi-layers and large proportions of N-doped edge planes. The materials serve as efficient metal-free electrocatalysts for hydrazine oxidation.
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Edge‐Plane‐Rich Nitrogen‐Doped Carbon Nanoneedles and Efficient Metal‐Free Electrocatalysts
Angewandte Chemie (International ed. in English), 2012Co-Authors: Rafael Silva, Jafar F. Al-sharab, Tewodros AsefaAbstract:CNN news: N-doped carbon Nanoneedles (CNNs) are synthesized by self-assembling core-shell nanostructures and nanoreactors around cellulose Nanoneedles, and subsequent graphitization. The resulting graphitic Nanoneedles (see picture) have well-organized graphitic multi-layers and large proportions of N-doped edge planes. The materials serve as efficient metal-free electrocatalysts for hydrazine oxidation.
Hui Ying Yang - One of the best experts on this subject based on the ideXlab platform.
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magnetic anisotropy in the ferromagnetic cu doped zno Nanoneedles
Applied Physics Letters, 2007Co-Authors: Tun Seng Herng, Shu Ping Lau, Hui Ying Yang, Masaki Tanemura, Lin Wang, J S ChenAbstract:Copper-doped ZnO (ZnO:Cu) Nanoneedles exhibiting room-temperature ferromagnetism were fabricated by an ion beam technique using Cu plate and ZnO film. A saturated magnetization moment of 0.698emu∕cm3 was found in the Nanoneedles when a field of 10kOe was applied perpendicular to the substrate, which was 15% larger than the field applied parallel to the substrate. The magnetic ordering of the Nanoneedles was enhanced significantly to 0.968emu∕cm3 after annealing of 400°C for 20min. However, the magnetic anisotropy at high field is vanished but an “easy plane” ferromagnetism becomes apparent at low field region. The possible mechanisms of the magnetic ordering and anisotropy in the ZnO:Cu Nanoneedles are discussed.
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Wavelength-tunable and high-temperature lasing in ZnMgO Nanoneedles
Applied Physics Letters, 2006Co-Authors: Hui Ying Yang, Shu Ping Lau, Masaki Tanemura, H. Hatano, Tatsuhiko Okita, Kar Seng Teng, Steve P. WilksAbstract:Zn1−xMgxO Nanoneedles were prepared by an ion-beam technique on Zn1−xMgxO thin films with Mg contents of up to 21at.%. The photoluminescence emission energies of the Zn1−xMgxO Nanoneedles measured at room temperature increased monotonically with Mg contents and it reached 3.6eV when x=0.21. Random laser action was observed in the Zn1−xMgxO Nanoneedles with x⩽0.1 at temperature ranging from 300to470K under 355nm optical excitation. The characteristic temperature of the Zn1−xMgxO Nanoneedles was determined to be 84K. The high-temperature lasing of the Zn1−xMgxO Nanoneedles are attributed to the high crystal quality of the Nanoneedles, enhancement of oscillator strength in nanostructures, and a self-compensation mechanism in random laser cavities.
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High-temperature random lasing in ZnO Nanoneedles
Applied Physics Letters, 2006Co-Authors: Hui Ying Yang, Shu Ping Lau, Masaki Tanemura, T. Okita, Agus Putu Abiyasa, H. HatanoAbstract:We report the high-temperature ultraviolet random laser action in ZnO Nanoneedles. The characteristic temperature of the ZnO nanoneedle lasers was derived to be 138K in the temperature range from 300to615K. The cavity length of the random lasers as a function of temperature was determined by Fourier transform spectroscopy. The cavity length decreased with an increase in temperature from ∼14μm at 300Kto∼2μm at 550K. The optical gain of the ZnO nanoneedle lasers at high temperature is attributed to a self-compensation mechanism in the cavity length.
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field emission from zinc oxide Nanoneedles on plastic substrates
Nanotechnology, 2005Co-Authors: Hui Ying Yang, Shu Ping Lau, Masaki Tanemura, T. Okita, L Huang, J Tanaka, Huey Hoon HngAbstract:The electron field emission from zinc oxide (ZnO) Nanoneedles on flexible plastic substrates is reported. ZnO thin films were first deposited on plastic substrates at 200 °C using a filtered cathodic vacuum arc technique; the films were then bombarded by Ar+ ion. After ion beam irradiation, high-density ZnO nanoneedle arrays were selectively formed on the thin films. The average diameter and length of the ZnO Nanoneedles is around 100 and 700 nm respectively. Field emission measurement showed a fairly low threshold voltage of 4.1 V µm−1 with a current density of 1 µA cm−2. The emission current density can be as high as 1 mA cm−2 at 9.6 V µm−1. The result establishes a method of fabricating a flexible field emitter, which should find practical applications in vacuum electronic devices.
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Laser action in ZnO Nanoneedles selectively grown on silicon and plastic substrates.
Applied Physics Letters, 2005Co-Authors: Shu Ping Lau, Hui Ying Yang, Masaki Tanemura, T. Okita, H. Hatano, Huey Hoon HngAbstract:An ion-beam technique has been employed to fabricate nanoscale needlelike structures in ZnO thin films on silicon and plastic substrates at room temperature. The ZnO Nanoneedles showed a single-crystalline wurtzite structure, the stem of which was around 100 nm in diameter. The sharp tips of the Nanoneedles exhibited an apex angle of 20° as measured by transmission electron microscopy. Room-temperature ultraviolet random lasing action was observed in the ZnO nanoneedle arrays under 355 nm optical excitation
