以非接觸方法直接估計小能隙石墨烯之機械模數

大面積的氮化硼摻雜石墨烯 (BNG)已經在先前的研究中被成功合成出來, 並且擁有高達約600 meV 的能隙。到目前為止,還沒有相關的文獻不是用理論模擬的方式去估計BNG的力學系數。本論文展示了ㄧ項新方法去估計低氮化硼濃度BNG的面內剛度。本方法是利用拉曼光譜2D峰值的位移量去測量石墨烯與低氮化硼濃度BNG在底下基板被拉伸的情況下所承受的實際應變,再將此測量出來的應變與已知的石墨烯面內剛度套入理論的公式去得到我們想要的結果。而2at.%氮化硼濃度BNG (2BNG)的面內剛度大約為 309 N/m.此外,我們還利用實驗得知2BNG的電阻對應力的敏感度約為石墨烯的三倍。此結果顯示2BNG是一個比石墨烯更適合在未來作為應變規的材料。

關鍵字

氮化硼參雜；石墨烯；化學氣相沉積；拉曼光譜；面內剛度；應變規

並列摘要

Graphene has become a popular material for various electronic applications because of its excellent physical properties, but the lack of band gap limits its performance in these electronic devices. Recently, large-area few layers graphene co-doped with boron-nitride (BNG) has been successfully synthesized and it shows a significant band gap up to 600 meV in our previous studies. Determination of mechanical modulus of BNG is one of the key issues in the development of application in electro-mechanical system. But there is no experimental assessment about the mechanical modulus of the small band gap BNG in the literature. In this thesis, we have demonstrated a different approach to estimate the in plane stiffness of BNG with low BN concentration by estimating the strain induced by stretching the underside flexible substrate from the shift of Raman 2D peak. The in plane stiffness can be obtained from the estimated strains of both graphene and BNG and the well known in plane stiffness of graphene using a theoretical formula. The estimated in plane stiffness value of BNG with 2 at% BN concentration is about 309 N/m. Moreover, the conductivity of BNG has shown to be more sensitive than pristine graphene in response to externally applied strain. This result indicates that BNG is a more suitable future material for strain sensor application.

並列關鍵字

BN doping ； graphene ； chemical vapor deposition ； Raman spectrum ； in plane stiffness ； strain sensor

參考文獻

1. S.V. Morozov, K.S. Novoselov, M.I. Katsnelson, et al., Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer. Physical Review Letters, 2008. 100: p. 016602.

2. J.H. Chen, C. Jang, S. Xiao, et al., Intrinsic and Extrinsic Performance Limits of Graphene Devices on SiO2. Nature Nanotechnology, 2008. 3: p. 206-209.

3. C. Lee, X. Wei, J.W. Kysar, et al., Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene. Science, 2008. 321: p. 385-388.

4. R.R. Nair, P. Blake, A.N. Grigorenko, et al., Fine Structure Constant Defines Visual Transparency of Graphene. Science, 2008. 320: p. 1308.

5. A.K. Geim and K.S. Novoselov, The Rise of Graphene. Nature Materials, 2007. 6: p. 183 - 191.

國際替代計量

以非接觸方法直接估計小能隙石墨烯之機械模數

全文下載

主題瀏覽