Ni Zhen Hua, Yu Ting, Lu Yun Hao, Wang Ying Ying, Feng Yuan Ping, Shen Ze Xiang
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.
ACS Nano. 2008 Nov 25;2(11):2301-5. doi: 10.1021/nn800459e.
Graphene was deposited on a transparent and flexible substrate, and tensile strain up to approximately 0.8% was loaded by stretching the substrate in one direction. Raman spectra of strained graphene show significant red shifts of 2D and G band (-27.8 and -14.2 cm(-1) per 1% strain, respectively) because of the elongation of the carbon-carbon bonds. This indicates that uniaxial strain has been successfully applied on graphene. We also proposed that, by applying uniaxial strain on graphene, tunable band gap at K point can be realized. First-principle calculations predicted a band-gap opening of approximately 300 meV for graphene under 1% uniaxial tensile strain. The strained graphene provides an alternative way to experimentally tune the band gap of graphene, which would be more efficient and more controllable than other methods that are used to open the band gap in graphene. Moreover, our results suggest that the flexible substrate is ready for such a strain process, and Raman spectroscopy can be used as an ultrasensitive method to determine the strain.
石墨烯沉积在透明且可弯曲的基底上，通过沿一个方向拉伸基底施加高达约0.8%的拉伸应变。应变石墨烯的拉曼光谱显示，由于碳 - 碳键的伸长，2D和G带出现显著的红移（分别为每1%应变 -27.8和 -14.2 cm⁻¹）。这表明单轴应变已成功施加于石墨烯上。我们还提出，通过对石墨烯施加单轴应变，可以实现K点处的可调带隙。第一性原理计算预测，在1%单轴拉伸应变下，石墨烯的带隙打开约为300 meV。应变石墨烯为实验调节石墨烯带隙提供了一种替代方法，这将比用于打开石墨烯带隙的其他方法更高效、更可控。此外，我们的结果表明，柔性基底适用于这种应变过程，拉曼光谱可作为一种超灵敏方法来确定应变。
