Ultrafast Charge Transfer at Monolayer Graphene Surfaces with Varied Substrate Coupling
详细信息 查看全文
- 作者：Silvano Lizzit ; Rosanna Larciprete ; Paolo Lacovig ; Krassimir L. Kostov ; Dietrich Menzel
- 刊名：ACS Nano
- 出版年：2013
- 出版时间：May 28, 2013
- 年：2013
- 卷：7
- 期：5
- 页码：4359-4366
- 全文大小：626K
- 年卷期：v.7,no.5(May 28, 2013)
- ISSN：1936-086X
文摘
The charge transfer rates of a localized excited electron to graphene monolayers with variable substrate coupling have been investigated by the core hole clock method with adsorbed argon. Expressed as charge transfer times, we find strong variations between 3 fs (on graphene 鈥渧alleys鈥?on Ru(0001)) to 16 fs (quasi-free graphene on SiC, O/Ru(0001), or SiO2/Ru). The values for the 鈥渉ills鈥?on Gr/Ru and on Gr/Pt(111) are in between, with the ratio 1.7 between the charge transfer times measured on 鈥渉ills鈥?and 鈥渧alleys鈥?of Gr/Ru. We discuss the results for Gr on metals in terms of hybridized Ru鈥揅 orbitals, which change with the relative Gr鈥揜u alignment and distance. The charge transfer on the decoupled graphene layers must represent the intrinsic coupling to the graphene empty 蟺* states. Its low rate may be influenced by processes retarding the spreading of charge after transfer.