Effects of Al on epitaxial graphene grown on 6H-SiC(0001)
نویسندگان
چکیده
Aluminum was deposited on epitaxial monolayer-grown graphene on SiC (0001). The effects of annealing up to 1200 °C on the surface and interface morphology, chemical composition, and electron band structure were analyzed in situ by synchrotron-based techniques at the MAX Laboratory. After heating at around 400 °C, Al islands or droplets are observed on the surface and the collected Si 2p, Al 2p, and C 1s core levels spectra indicate Al intercalation at the graphene SiC interface. Also, the original single π-band splits into two, indicating decoupling of the carbon buffer layer and the formation of a quasi-freestanding bilayer-like electronic structure. Further heating at higher temperatures from 700 to 900 °C yields additional chemical reactions. Broader core level spectra are then observed and clear changes in the π-bands near the Dirac point are detected. More electron doping was detected at this stage since one of the πbands has shifted to about 1.1 eV below the Fermi level. Different ordered phases of (7 × 7), (4 × 4), (1 × 1)Al, and (1 × 1)G were also observed on the surface in this temperature range. The original single π-band was restored after heating at ~1200 °C, although an Al signal was still able to be detected.
منابع مشابه
Understanding the STM images of epitaxial graphene on a reconstructed 6H-SiC(0001) surface: the role of tip-induced mechanical distortion of graphene.
Epitaxial graphene (EG) grown on an annealed 6H-SiC(0001) surface has been studied under ultra-high vacuum (UHV) conditions by using a combined dynamic-scanning tunneling microscope/frequency modulation-atomic force microscope (dynamic-STM/FM-AFM) platform based on a qPlus probe. STM and AFM images independently recorded present the same hexagonal lattice of bumps with a 1.9 nm lattice period, ...
متن کاملMicro-Raman analysis of the influence of hydrogen intercalation on the epitaxial graphene grown on 4H-SiC(0001) substrate K.Grodecki
It is commonly accepted that properties of epitaxial graphene (EG) grown on SiC are determined by interaction with substrate. It was found, that hydrogen intercalation of EG grown on SiC(0001) substrates by sublimation is a promising method to increase the mobility of carriers [1]. As verified by Raman spectroscopy [2] sublimation grown samples show much stronger interaction with the SiC substr...
متن کاملAtomic-scale imaging and manipulation of ridges on epitaxial graphene on 6H-SiC(0001).
Ridges are observed on epitaxial graphene on 6H-SiC(0001) by scanning tunneling microscopy (STM). Atomic resolution imaging reveals that they are in fact bulged regions of the graphene layer, occurring as a result of bending and buckling to relieve the compressive strain. Furthermore, their length, direction, and distribution can be manipulated, and new ones can even be created by the tip-surfa...
متن کاملLarge homogeneous mono-/bi-layer graphene on 6H-SiC(0001) and buffer layer elimination
In this paper we discuss and review results of recent studies of epitaxial growth of graphene on silicon carbide. The presentation is focused on high quality, large and uniform layer graphene growth on the SiC(0001) surface and results of using different growth techniques and parameters are compared. This is an important subject because access to high quality graphene sheets on a suitable subst...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2015