resumo
Surface properties of multilayer graphene (MLG) were studied by Kelvin Probe and Electric-field Force Microscopies (KPFM and EFM). Using KPFM, we observed an increase in the work function of MLG with increasing thickness. This is attributed to the surface -electrons of p(z) orbitals shifting the Fermi level away from the Dirac point. EFM measurements indicate that the EFM phase increases with DC electric fields (-5V V 5V) applied to the probe. The parabolic phase-shift dependence is pertaining to the electrostatic interaction produced at the tip-MLG interface. These results provide future directions in band-gap engineering of graphene-based devices.
palavras-chave
EPITAXIAL GRAPHENE; SINGLE
categoria
Materials Science; Physics
autores
Vidyasagar, R; Camargo, B; Romanyuk, K; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Jubilado
Konstantin Nikolaevich Romanyuk
Investigador Júnior
Reddithota Vidyasagar
Bolseiro de pós-Doutoramentoagradecimentos
This work is supported by the Foundation for Science and Technology of Portugal, grants SFRH/BPD/104887/2014 (RV) and SFRH/BPD/88362/2012 (KR). KR and ALK are grateful to the Russian Foundation for Basic Research (grant No. 16-29-14050-ofr-m) and Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006) for the financial support. Part of this work was developed in the scope of Project CICECO-Aveiro Institute of Materials (ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and, when applicable, cofinanced by FEDER under the PT2020 Partnership Agreement.