中低能质子束辐照单层石墨烯的损伤效应

发布时间：2018-07-23 13:06

【摘要】：单层石墨烯,一种由单层碳原子以sp2杂化方式形成的二维蜂巢状材料,厚度仅有0.335 nm,是目前世界上最薄、最坚硬、强度最高的材料。由于优异的材料性能,石墨烯在工业众多领域内有着巨大潜力和发展前景。但由于其带隙为零,一定程度上限制了在电子器件方面更进一步的应用。为了通过离子辐照在石墨烯中引入缺陷进而打开带隙并研究离子束与二维材料相互作用的机理与三维块体材料的异同。本工作研究了不同能量的质子束对SLG的辐照损伤效应,主体工作分为三部分。1、750 keV、1 MeV的质子束对硅基底SLG的辐照损伤效应。2、1 MeV质子束辐照不同基底的SLG的辐照损伤效应比较。3、20 keV、150 keV、250 keV、400 keV、800 keV、2.2 MeV质子束对硅基底和自持SLG的辐照损伤效应对比。通过对比辐照前后的石墨烯样品的拉曼光谱,我们发现:1、当质子能量为150-400 keV之间时,其轰击硅基底单层石墨烯引起的损伤与质子在硅和碳中的能损呈现相反的趋势,即能损越小,损伤越大。这一点与高能数个MeV区间的实验特性完全相反。经过多次在不同加速器下重复验证实验,以及每块靶材上进行均匀分布的数十个拉曼点测试和表征,充分证实了该主要实验发现的可靠性。2、在100-400 keV能区,质子束在硅基底单层石墨烯上引起的损伤远远大于其在自持单层石墨烯上造成的损伤。这一特性与MeV能区又有着明显的不同,MeV及以上能区,国际上实验均发现自持单层石墨烯的损伤大于有基底单层石墨烯的损伤。除以上发现外,本研究工作还得到以下实验结果:1、质子能区在750 keV~2.2 MeV时,ID/IG随着入射质子能损的增大而增大,与SRIM程序模拟结果趋势一致;缺陷间平均距离LD随入射质子能量的增大而增大;缺陷密度nD随入射质子能量的增大而减小。这表明该能区的质子在石墨烯中的损伤效应与三维材料相似。2、能量为1 MeV的质子束对硅基底SLG的损伤效应大于铜基底SLG。
[Abstract]:Graphene monolayer, a two-dimensional honeycomb material formed by monolayer carbon atom and sp2 hybrid, is the thinnest material with a thickness of only 0.335 nm, which is the thinnest, hardest and strongest material in the world. Because of its excellent material properties, graphene has great potential and development prospect in many fields of industry. However, due to the zero band gap, the further application of electronic devices is limited to some extent. In order to introduce defects into graphene by ion irradiation and to open the band gap, the mechanism of interaction between ion beam and two-dimensional material and the similarities and differences of three-dimensional bulk materials were studied. In this work, the radiation damage effects of proton beams with different energies on SLG were studied. Radiation damage effect of 1 750 Kev 1 MeV proton beam on SLG on silicon substrate; radiation damage effect of 2 MeV proton beam on SLG on different substrates; radiation damage effect on Si substrate and self sustaining SLG by MeV proton beam with 20 Kev ~ 150 Kev ~ (150) Kev ~ (250) Kev ~ (400) Kev ~ (800) Kev ~ (2) MeV The damage effect was compared. By comparing the Raman spectra of graphene samples before and after irradiation, we find that when the protons energy is between 150 and 400 keV, the damage caused by the bombardment of graphene monolayers on silicon substrates is opposite to the energy loss of protons in silicon and carbon. That is, the smaller the energy loss, the greater the damage. This is contrary to the experimental characteristics of several high energy MeV regions. After repeated experiments at different accelerators, and dozens of Raman points with uniform distribution on each target, the reliability of the main experimental findings. Is fully confirmed in the 100-400 keV energy region. The damage caused by proton beam on monolayer graphene on silicon substrate is much larger than that on self-sustaining monolayer graphene. This characteristic is obviously different from that in MeV energy region. It is found that the damage of self-sustaining monolayer graphene is greater than that of substrate monolayer graphene. In addition to the above findings, the following experimental results: 1: 1, ID-IG increase with the increase of the incident proton energy loss at the proton energy region of 750 keV~2.2 MeV, which is consistent with the simulation results of the SRIM program. The average distance between defects increases with the increase of the incident proton energy, and the defect density nD decreases with the increase of the incident proton energy. It is shown that the damage effect of proton in this energy region in graphene is similar to that in 3D material. The damage effect of proton beam with energy of 1 MeV on SLG of silicon substrate is greater than that of copper substrate.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71

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