Ageing effects at graphene/germanium interface

• Published in: Applied surface science Vol. 497; p. 143779
• Main Authors: Mendoza, C.D., Maia da Costa, M.E.H., Freire, F.L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2019
• Subjects: AFM; Graphene/Ge; Raman spectroscopy; STM/STS; XPS; STM/STS; AFM; XPS; Raman spectroscopy; Graphene/Ge
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.143779

X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Raman spectroscopy and scanning tunnelling microscopy/spectroscopy (STM/STS) were used to study the effects of a long exposition to the air moisture of the interface between graphene and Ge (110) substrate. The single-layer graphene was grown by chemical vapour deposition (CVD) directly on Ge. The Raman and XPS results indicated that oxidation occurs slowly probably due to the diffusion of oxygen containing species through short-circuits like defects and grain boundaries present in the graphene sheet, as revealed by AFM and STM. In a long time-scale, the oxidation process resulted in a decoupling between graphene and germanium and a modification of the local density of states measured by STS.
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•Single-layer graphene synthesized on Ge (110) substrates by CVD.•Samples were exposed to air and ageing effects were monitored.•XPS results revealed the progressive oxidation of germanium.•Raman results suggested a decoupling between graphene and Ge after ten months.•STS measurements showed changes on LDOS of graphene/Ge (110) interface.