Evidence for re-crystallization process in the irradiated graphite with heavy ions obtained by Raman spectroscopy
Evidence for re-crystallization process in the irradiated graphite with heavy ions obtained by Raman spectroscopy
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通过拉曼光谱获得重离子辐照石墨中重结晶过程的证据
DOI：
10.1016/j.carbon.2016.01.076
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发表时间：
2016-05
期刊：
影响因子：
10.9
通讯作者：
Youmei Sun
中科院分区：
文献类型：
--
作者：
Pengfei Zhai;Jie Liu;Jian Zeng;Jinglai Duan;Lijun Xu;Huijun Yao;Hang Guo;Shengxia Zhang;Mingdong Hou;Youmei Sun
用40.5 MeV112Sn离子辐照高取向热解石墨（HOPG），辐照量为1 × 1012-1 × 1014ions/cm2。在~ 864 cm−1处观察到一个新的拉曼带，该带随着辐照量的增加而增长。在HOPG和天然石墨晶体边缘面上的拉曼光谱中，只有当入射光垂直于基面上偏光时，该带才会被分配到面外拉曼非活动模式b2gmode，由于边缘晶格结构的轻微重排而成为拉曼活动模式。然而，我们首先在入射光偏振平行于基底面的辐照HOPG基底面的拉曼光谱中获得了该波段。然后，利用半波片改变入射光在HOPG基面上的偏振方向。864 cm−1处的波段强度几乎与入射光的偏振方向无关。我们认为在离子辐照过程中，石墨形成了具有随机晶格取向的再结晶，从而产生了b2gband。透射电镜图像证实了这一结论，表明有一些随机取向的纳米级石墨晶体被无定形碳包围。
Highly oriented pyrolytic graphite (HOPG) was irradiated with 40.5 MeV112Sn ions at a range of fluence: 1 × 1012–1 × 1014ions/cm2. A new Raman band was observed at ∼864 cm−1which grows with increasing the irradiation fluence. This band has been observed in Raman spectra of HOPG and natural graphite crystal edge planes, only when the incident light is polarized perpendicular to the basal planes and it has been assigned to the out-of-plane Raman-inactiveB2gmode which becomes Raman active due to a slight rearrangement of lattice structure at the edge. However, we first obtained this band in Raman spectra of basal planes of irradiated HOPG with the polarization of the incident light parallel to the basal planes. Then, a half-wave plate was used to change the polarization direction of the incident light in the HOPG basal planes. The intensity of the band at 864 cm−1is almost independent of the incident light polarization direction. We suggest that re-crystallized graphite with random lattice orientations are formed during ion irradiation, which gives rise to theB2gband. The conclusion is confirmed by transmission electron microscopy images, showing that there are some randomly orientated nanoscale graphite crystals surrounded by amorphous carbon.
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影响因子：
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影响因子：
3.7
作者：
Liu, J;Neumann, R;Müller, C
通讯作者：
Müller, C