• Title, Summary, Keyword: boron nitride

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Molecular Dynamics Simulations of Nanomemory Element Based on Boron Nitride Nanotube-to-peapod Transition

  • Hwang Ho Jung;Kang Jeong Won;Byun Ki Ryang
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.6
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    • pp.227-232
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    • 2004
  • We investigated a nonvolatile nanomemory element based on boron nitride nanopeapods using molecular dynamics simulations. The studied system was composed of two boron-nitride nanotubes filled Cu electrodes and fully ionized endo-fullerenes. The two boron-nitride nanotubes were placed face to face and the endo-fullerenes came and went between the two boron-nitride nanotubes under alternatively applied force fields. Since the endo-fullerenes encapsulated in the boron-nitride nanotubes hardly escape from the boron-nitride nanotubes, the studied system can be considered to be a nonvolatile memory device. The minimum potential energies of the memory element were found near the fullerenes attached copper electrodes and the activation energy barrier was $3{\cdot}579 eV$. Several switching processes were investigated for external force fields using molecular dynamics simulations. The bit flips were achieved from the external force field of above $3.579 eV/{\AA}$.

Preparation of Hexagonal Boron Nitride from Boron Oxide and Sodium Amide (산화붕소의 소듐아미드로부터 육방정 질화붕소의 합성)

  • 손영국;장윤식;오기동
    • Journal of the Korean Ceramic Society
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    • v.27 no.7
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    • pp.869-876
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    • 1990
  • Hexagonal boron nitride was synthesized from boron oxide and sodium amide in ammonia gas stream. The reaction mechanisms and characteristics of as synthesized boron nitride was investigated by means of TG, DTA, IR, XRD, SEM and PSA. The results are ; 1) hexagonal boron nitride was synthesized from reactions at temperatures above 40$0^{\circ}C$ 2) Sodium metaborate was present as by-product after reaction so that the reaction mechanism is reduced as follows : 2B2O3+3NaNH2longrightarrowBN+3NaBO2+2NH3. 3) boron nitride obtained at the reaction temperature below 40$0^{\circ}C$ is found to have random layer strudcture but the structure transits to ordered layer structure rapidly with increasing reaction temperature, showing separation of (101) differaction line from (10)band in XRD pattern of the reaction product at 50$0^{\circ}C$.

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Boron nitride based processing aids

  • Hatzikiriakos, Savvas G.;Rathod, Nimish
    • Korea-Australia Rheology Journal
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    • v.15 no.4
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    • pp.173-178
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    • 2003
  • Boron nitride is a new processing aid that is capable of eliminating gross melt fracture in several polymer processing operations. Its combinations with other processing aids i.e. fluoropolymers offer additional possibilities of obtaining enhanced processing aids that may take the processes to rates not realized before. A variety of different such combinations are discussed in this paper. The essential componenets are (1) boron nitride capable of eliminating gross melt fracture and (2) suitable lubricant capable of eliminating surface melt fracture such as stearates for the polyolefin processing and polyethylenes for the processing of fluoropolymers.

Direct synthesis of Graphene/Boron nitride stacked layer by CVD on Cu foil

  • Moon, Youngwoong;Park, Jonghyun;Park, Sijin;Kim, Hyungjun;Hwang, Chanyong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.344.1-344.1
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    • 2016
  • Recently, graphene has shown great characteristic of electrical conductivity, strength, and elasticity. However, due to edge unstable and metallic properties, it is difficult to use as a semiconductor devices. The solution of such problems has been sought a way to use the boron nitride in a stacked layer structure. By graphene and boron nitride stacked layer structure on silicon substrate, the electron mobility is improved and deteriorated results in semiconductor properties. In this study, to make layered structure, we developed direct synthesis method for graphene on boron nitride. By using Raman technique, the directly stacked layer structure is in good agreement with measurements on each of the attributes.

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Effect of Silicon Nitride Whisker Content on the Flexural Strength of Silicon Nitride-Boron Nitride-Silicon Carbide Multi-Layer Composites

  • Park, Dong-Soo;Cho, Byung-Wook
    • Journal of the Korean Ceramic Society
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    • v.40 no.9
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    • pp.832-836
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    • 2003
  • Multi-layer ceramic composites were prepared by tape casting followed by hot pressing using silicon nitride layer with silicon nitride whiskers, silicon nitride layer with silicon carbide particles and boron nitride-alumina layer. The whiskers were aligned during the casting. As the whisker content of the silicon nitride layer was increased up to 10 wt%, the flexural strength of the multi-layer composite was increased. However, further increase of the whisker content in the layer resulted in a rapid decrease of the strength of the composite. The results suggest that the strength of multi-layer ceramic composite showing non-catastrophic failure behavior can be significantly improved by incorporating the aligned whiskers in the layers.

Relation between the Concentration of Hexagonal Boron Nitride Nano-Sheets Dispersed in Pure Water and Their Width and Height (초순수 용매 내 육방정 질화붕소 나노시트의 농도와 크기의 관계)

  • Cho, Dae-Hyun;Park, Miyoung;Ha, Seonghun
    • Tribology and Lubricants
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    • v.35 no.6
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    • pp.343-349
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    • 2019
  • According to a report in 2011, hexagonal boron nitride demonstrated good solubility in pure water, even without surfactants or organic functionalization. Hexagonal boron nitride nanosheets are an effective lubricant additive, and their solubility in pure water has motivated lubrication engineers to utilize aqueous solutions containing these nanosheets as water-based lubricants. In this study, we measure the width and height of the hexagonal boron nitride nanosheets dispersed in pure water by using the Zetasizer and atomic force microscopy. Without surfactants or functionalization, aqueous solutions containing 0.10, 0.07, 0.05, and 0.01 wt% of hexagonal boron nitride nanosheets are synthesized via sonication-assisted hydrolysis. The Zetasizer provides only a one-dimensional size of approximately 410 nm, regardless of the concentration of the solution. Thus, it does not allow the estimation of the shape of the nanosheet. To acquire the three-dimensional size of the nanosheets, atomic force microscopy is employed. The aqueous solutions containing 0.10, 0.07, 0.05, and 0.01 wt% of the hexagonal boron nitride nanosheets show average values of 740, 450, 700, and 610 nm in width, and 37, 26, 33, and 32 nm in thickness, respectively. No significant trend is observed between the concentration of the solution and size of the nanosheets. Therefore, when preparing a water-based lubricant, it may be appropriate to adjust conditions such as ultrasonication time rather than the concentration.

Direct Growth of Graphene on Boron Nitride/Copper by Chemical Vapor Deposition

  • Jin, Xiaozhan;Park, J.;Kim, W.;Hwang, Chanyong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.590-590
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    • 2013
  • Direct growth of graphene using CVD method has been done on CVD grown boron nitride substrate. From the SEM image, we have shown that the size of grain of graphene could be clearly controlled by varying the amount of injected hydrocarbon. To convince the existence of graphene on boron nitride, XPS and Raman has been checked. Both B1s and N1s peaks in XPS spectra and the Raman peak around 1,370 $cm^{-1}$ demonstrated that boron nitride did remain after high temperature treatment during the graphene growth process. And along the graphene grain boundary, the Raman fingerprint of graphene was neatly appeared.

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Atomistic Study of III-Nitride Nanotubes (3족-질화물 나노튜브의 원자단위 연구)

  • 변기량;강정원;이준하;권오근;황호정
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.2
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    • pp.127-137
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    • 2004
  • We have investigated the structures, the energetic, and the nanomechanics of the single-wall boron-, aluminum-, and gallium-nitride nanotubes using atomistic simulations based on the Tersoff-type potential. The Tersoff-type potential for the III-nitride materials has effectively described the properties of the III-nitride nanotubes. Nanomechanics of boron-, aluminum-, and gallium-nitride nanotubes under the compression loading has been investigated and their Young's moduli were calculated.

Growth and Dissolve of Defects in Boron Nitride Nanotube

  • Lee, Jun-Ha;Lee, Hoong-Joo
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.3
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    • pp.23-25
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    • 2004
  • The defect formation energy of boron nitride (BN) nanotubes is investigated using molecular-dynamics simulation. Although the defect with tetragon-octagon pairs (4-88-4) is favored in the flat cap of BN nanotubes, BN clusters, and the growth of BN nanotubes, the formation energy of the 4-88-4 defect is significantly higher than that of the pentagon-heptagon pairs (5-77-5) defect in BN nanotubes. The 5-77-5 defect reduces the effect of the structural distortion caused by the 4-88-4 defect, in spite of homoelemental bonds.

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A study on a Boron-Nitride Nanotube as a Gigahertz Oscillator (기가헤르츠 오실레이터를 위한 BN 나노튜브 연구)

  • Lee, Jun-Ha
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.1
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    • pp.27-30
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    • 2007
  • The gigahertz oscillator behavior of double-walled boron-nitride nanotube (BNNT) was investigated by using classical molecular dynamics simulations. The BNNT oscillator characteristics were compared to carbon-nanotube (CNT) and hybrid-C@BNNT oscillators. The results show that the BNNT oscillators are higher than the van der Waals force of the CNT oscillator. Since the frictional effects of BNNT oscillators are higher than that of a CNT oscillator, the damping factors of BNNT and hybrid oscillators are higher than that of a CNT oscillator.

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