Growth of graphene on SiO2 with hexagonal boron nitride buffer layer
Growth of graphene on SiO2 with hexagonal boron nitride buffer layer
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DOI：
10.1016/j.apsusc.2018.12.186
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发表时间：
2019-05-01
影响因子：
6.7
通讯作者：
Sakai, Seiji
中科院分区：
文献类型：
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作者：
Entani, Shiro;Takizawa, Masaru;Sakai, Seiji
在绝缘体衬底上插入六方氮化硼（h-BN）缓冲层的石墨烯生长的单程工艺预期由于石墨烯和绝缘体之间的界面相互作用的减轻和衬底的平坦度的增强而产生石墨烯器件的电子传输性质的性能的显著改善。在这项研究中，我们成功地制备了石墨烯/h-BN/SiO2异质结构，通过直接化学气相沉积（CVD）没有机械转移过程。发现h-BN促进了石墨烯在SiO2上的生长，而没有h-BN层的石墨烯生长是非常困难的。利用显微拉曼光谱和近边X射线吸收精细结构（NEXAFS）光谱研究了石墨烯和六方氮化硼的电子结构。B和N K边NEXAFS表明，在h-BN/SiO2和石墨烯/h-BN/SiO2中均存在化学形式为BN 3-xOx（x = 1，2，3）的替位氧杂质。石墨烯/h-BN/SiO2中的O取代杂质的数量是h-BN/SiO2中的两倍，这被推测是由于在石墨烯生长期间与来自SiO2和甲醇的氧反应。石墨烯/h-BN/SiO2体系中石墨烯与h-BN的界面相互作用较弱。本研究表明，用CVD生长的h-BN层可以是石墨烯器件的上级缓冲层，其使得能够在其上直接生长石墨烯，并减少与绝缘体衬底的相互作用。
One-through process of graphene growth on insulator substrates with inserting a hexagonal boron nitride (h-BN) buffer layer is expected to yield significant improvements in performance of electron transport properties of graphene devices due to the alleviation of the interface interaction between graphene and insulators and the enhancement of the flatness of the substrate. In this study, we successfully fabricated a graphene/h-BN/SiO2 heterostructure by direct chemical vapor deposition (CVD) without mechanical transfer processes. It was found that h-BN promotes the growth of graphene on SiO2 whereas the graphene growth without the h-BN layer is extremely difficult. The electronic structures of graphene and h-BN were investigated by using micro-Raman spectroscopy and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The B and N K-edge NEXAFS revealed that substitutional oxygen impurities with the chemical form of BN3-xOx (x = 1, 2, 3) are present in both h-BN/SiO2 and graphene/h-BN/SiO2. The number of O substitutional impurities is two times larger in graphene/h-BN/SiO2 than in h-BN/SiO2, which is presumed to be due to the reaction with oxygen from SiO2 and methanol during the graphene growth. The interfacial interaction between graphene and h-BN was found to be weak in graphene/h-BN/SiO2. The present study shows that the h-BN layer grown with CVD can be a superior buffer layer for graphene devices which enables direct graphene growth on it and to decrease the interactions with insulator substrates.