Raman spectroscopy on hydrogenated graphene under high pressure
Raman spectroscopy on hydrogenated graphene under high pressure
复制标题
DOI：
10.1016/j.carbon.2019.09.077
复制
发表时间：
2020-01-01
期刊：
影响因子：
10.9
通讯作者：
Goncharov, Alexander F.
中科院分区：
文献类型：
--
作者：
Pakornchote, Teerachote;Geballe, Zachary M.;Goncharov, Alexander F.
我们采用激光加热金刚石对顶砧（LHDAC）合成氢化单层石墨烯（SLG），并探索了石墨烯（完全氢化SLG）的途径。我们采用拉曼光谱法研究了铜基底上的SLG，该基底分别压缩至8 GPa和20 GPa，压缩应变分别为2.2%和4.6%，然后进行激光加热。激光加热后，G峰和2D峰出现红移，然后在减压过程中形成磁滞回线。这种现象可能是由于两种机制中的一种或两种：在大量氢化的SLG中形成C-H化学键，以及SLG和Cu衬底之间的摩擦应力减小，导致SLG晶格向其独立平衡结构弛豫。G和2D峰之间的相关性也改变显着激光加热后，在8 GPa，类似的空穴掺杂实验中测得的相关性。最后，在减压至环境压力之后，残留的氢保持与石墨烯层键合，并且氢的量作为样品被激光加热的压力的函数而增加。(C)2019爱思唯尔有限公司版权所有。
We applied laser-heating in diamond anvil cells (LHDAC) to synthesize a hydrogenated single-layer graphene (SLG) and to explore the pathway toward graphane (fully hydrogenated SLG). We employed Raman spectroscopy to investigate SLG on a Cu substrate that was compressed up to 8 GPa and 20 GPa with 2.2% and 4.6% compressive strain, respectively, followed by laser-heating. After laser-heating, G and 2D peaks exhibit a redshift, and then form a hysteresis loop during decompression. This phenomenon can be due to either of two mechanisms, or both; the formation of C-H chemical bonds in massive hydrogenated SLG, and a reduction of the frictional stress between SLG and Cu substrate causing a relaxation of SLG lattice toward its free-standing equilibrium structure. The correlation between G and 2D peaks also changes significantly after laser-heating at 8 GPa, resembling the correlation measured in hole-doping experiments. Finally, residual hydrogen remains bonded to the graphene layer after decompression to ambient pressure, and the amount of hydrogen increases as a function of pressure at which the sample was laser-heated. (C) 2019 Elsevier Ltd. All rights reserved.