Evaluation of thickness and oxidation state of graphene/Cu(111)/AlO substrates using photoelectron spectroscopy

光電子分光を用いたグラフェン/Cu(111)/AlO基板の酸化と膜厚の評価

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

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

CVD growth of graphene on Cu substrates is one of the most applicable methods to obtain large area graphene. In this study, we have performed the circumstantial analysis of C 1s and O 1s photoelectron spectra in the graphene/Cu(111) substrate to clarify the annealing temperature dependence of oxidation state of graphene and the Cu substrate and graphene thickness. C 1s photoelectron spectra of a pristine graphene/Cu substrate can be divided by seven peaks. The defect peak derived from sp bonding and oxide peaks clearly observed at 373K. At this time, the Cu substrate is also oxidized and CuO films are formed at the interface. When this sample was annealed in vacuum, graphene oxide peaks of decrease rapidly with increasing temperature, and CuO is completely reduced at 633K. However, graphene oxide can not be reduced completely by annealing even at 1073K, and 4% of oxide still remains in graphene.