• 제목/요약/키워드: Thick graphene

검색결과 4건 처리시간 0.059초

Thick Graphene Embedded Metal Heat Spreader with Enhanced Thermal Conductivity

  • Park, Minsoo;Chun, Kukjin
    • 센서학회지
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    • v.23 no.4
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    • pp.234-237
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    • 2014
  • In this paper, a copper foil-thick grapheme (thin graphite sheet)-copper foil structure is reported to achieve mechanically strong and high thermal conductive layer suitable for heat spreading components. Since graphene provides much higher thermal conductivity than copper, thick graphene embedded copper layer can achieve higher effective thermal conductivity which is proportional to graphene/copper thickness ratio. Since copper is nonreactive with carbon material which is graphene, chromium is used as adhesion layer to achieve copper-thick graphene-copper bonding for graphene embedded copper layer. Both sides of thick graphene were coated with chromium as an adhesion layer followed by copper by sputtering. The copper foil was bonded to sputtered copper layer on thick graphene. Angstrom's method was used to measure the thermal conductivity of fabricated copper-thick graphene-copper structure. The thermal conductivity of the copper-thick graphene-copper structures is measured as $686W/m{\cdot}K$ which is 1.6 times higher than thermal conductivity of pure copper.

In-Situ Heat Cooling using Thick Graphene and Temperature Monitoring with Single Mask Process

  • Kwack, Kyuhyun;Chun, Kukjin
    • 센서학회지
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    • v.24 no.3
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    • pp.155-158
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    • 2015
  • In this paper, in-situ heat cooling with temperature monitoring is reported to solve thermal issues in electric vehicle (EV) batteries. The device consists of a thick graphene cooler on top of the substrate and a platinum-based resistive temperature sensor with an embedded heater above the graphene. The graphene layer is synthesized by using chemical vapor deposition directly on the Ni layer above the Si substrate. The proposed thick graphene heat cooler does not use transfer technology, which involves many process steps and does not provide a high yield. This method also reduces the mechanical damage of the graphene and uses only one photomask. Using this structure, temperature detection and cooling are conducted simultaneously using one device. The temperature coefficient of resistance (TCR) of a $1{\times}1mm^2$ temperature sensor on 1-$\grave{i}m$-thick graphene is $1.573{\times}10^3ppm/^{\circ}C$. The heat source cools down $7.3^{\circ}C$ from $54.4^{\circ}C$ to $47.1^{\circ}C$.

Raman Spectroscopy Studies of Graphene Nanoribbons and Chemical Doping in Graphene

  • Ryu, Sun-Min
    • 한국진공학회:학술대회논문집
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    • pp.15-15
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    • 2011
  • Atom-thick graphene membrane and nano-sized graphene objects (NGOs) hold substantial potential for applications in future molecular-scale integrated electronics, transparent conducting membranes, nanocomposites, etc. To realize this potential, chemical properties of graphene need to be understood and diagnostic methods for various NGOs are also required. To meet these needs, chemical properties of graphene and optical diagnostics of graphene nanoribbons (GNRs) have been explored by Raman spectroscopy, AFM and STM scanning probes. The first part of the talk will illustrate the role of underlying silicon dioxide substrates and ambient gases in the ubiquitous hole doping of graphene. An STM study reveals that thermal annealing generates out-of-plane deformation of nanometer-scale wavelength and distortion in $sp^2$ bonding on an atomic scale. Graphene deformed by annealing is found to be chemically active enough to bind molecular oxygen, which leads to a strong hole-doping. The talk will also introduce Raman spectroscopy studies of GNRs which are known to have nonzero electronic bandgap due to confinement effect. GNRs of width ranging from 15 nm to 100 nm have been prepared by e-beam lithographic patterning of mechanically exfoliated graphene followed by oxygen plasma etching. Raman spectra of narrow GNRs can be characterized by upshifted G band and strong disorder-related D band originating from scattering at ribbon edges. Detailed analysis of the G, D, and 2D bands of GNRs proves that Raman spectroscopy is still a reliable tool in characterizing GNRs despite their nanometer width.

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그래핀 기반 기체 분리막의 연구동향 및 전망 (Current Status and Perspectives of Graphene-based Membranes for Gas Separation)

  • 유병민;박호범
    • 멤브레인
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    • v.27 no.3
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    • pp.216-225
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    • 2017
  • 원자 수준의 두께를 가지는 그래핀 단일층이 흑연으로부터 박리되어 구현된 이래로, 그래핀은 2차원 소재의 활용 가능성을 연 물질로서 각광받고 있으며, 그래핀 고유의 뛰어난 물리적 특성으로 인하여 활발히 연구되고 있다. 특히 분리막 분야는 그래핀과 산화 그래핀이 활용 가능한 가장 중요한 분야 중의 하나로서, 최근의 다양한 시뮬레이션 연구를 통하여 그 가능성이 입증되고 있다. 그래핀과 산화 그래핀은 원자 수준의 얇은 두께, 뛰어난 기계적 강도, 높은 수준의 내화학성, 기공생성이 가능한 2차원 구조 또는 기체 확산 유로 생성이 가능한 적층 구조 등 분리막 소재로서 매우 유리한 특성들을 보유하고 있음이 밝혀졌다. 본 총설에서는 그래핀과 산화 그래핀의 고유 특성을 기반으로 기체 분리막 분야로의 응용 가능성과 현재까지의 개발 현황 및 향후 전망에 대하여 논하고자 한다.