Substrate and atmosphere influence on oxygen p-doped graphene

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• 作者：Aurora Piazza^a ; ^b ; ^c ; Filippo Giannazzo^a ; Gianpiero Buscarino^b ; Gabriele Fisichella^a ; Antonino La Magna^a ; Fabrizio Roccaforte^a ; Marco Cannas^b ; Franco Mario Gelardi^b ; Bruno Pignataro^b ; Michelangelo Scopelliti^b ; Simonpietro Agnello^b ; ^{simonpietro.agnello@unipa.it" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Carbon
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：107
• 期：Complete
• 页码：696-704
• 全文大小：2501 K

文摘

The mechanisms responsible for p-type doping of substrate supported monolayer graphene (Gr) by thermal treatments in oxygen ambient have been investigated by micro-Raman spectroscopy, atomic force microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), considering commonly employed dielectric substrates, such as SiO₂ and Al₂O₃ thin films grown on Si. While a high p-type doping (∼10¹³ cm⁻²) is observed for Gr on SiO₂, no significant doping is found for Gr samples on the Al₂O₃ substrate, suggesting a key role of the Gr/SiO₂ interface states in the trapping of oxygen responsible for the Gr p-type doping. Furthermore, we investigated the doping stability of Gr on SiO₂ during subsequent thermal treatments in nitrogen (N₂), carbon dioxide (CO₂), water (H₂O) or in vacuum controlled atmospheres. These processes induce only minor effects on the doping of Gr but for H₂O and principally affect its defectiveness, suggesting that the literature reported air influence on the doping depends on water present in the atmosphere.