Vacuum annealing formation of graphene on diamond C(111) surfaces studied by real-time photoelectron spectroscopy

リアルタイム光電子分光によるダイヤモンドC(111)表面上でのグラフェンの真空加熱形成

小川 修一*; 山田 嵩壽*; 吉越 章隆 ; 石塚 眞治*; 渡辺 大輝*; 長谷川 雅考*; 寺岡 有殿; 高桑 雄二*

Ogawa, Shuichi*; Yamada, Toshitaka*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Watanabe, Daiki*; Hasegawa, Masataka*; Teraoka, Yuden; Takakuwa, Yuji*

Graphene on a diamond layer is required for fabrication of a graphene transistor. It has been reported the graphitization of diamond C(111) surface by annealing in vacuum. The aim of this study is to identify the sp2-bonded carbon layer and to clarify the grafitization mechanism on the diamond C(111) surface. Real-time photoemission spectroscopy using synchrotron radiation and ultraviolet was employed during annealing. The C 1s photoelectron spectra showed two peaks. The high binding energy (HBC) peak is attributed the bulk diamond, and the low binding energy (LBC) peak corresponds to the surface component of diamond C(111)-21 structure. The increase of LBC above 1173 K is not due to the increase of surface photoemission, but increase of sp2 component of graphene carbon. The graphitization of diamond was also indicated in C 1s energy loss spectra and ultraviolet spectra. Based on these results, the formation process of graphene on diamond is proposed.