Raman spectroscopic characterizations of graphene on oxide substrates for remote epitaxy.

Graphene layers placed on SrTiO₃ single-crystal substrates, i.e., templates for remote epitaxy of functional oxide membranes, were investigated using temperature-dependent confocal Raman spectroscopy. This approach successfully resolved distinct Raman modes of graphene that are often untraceable in conventional measurements with non-confocal optics due to the strong Raman scattering background of SrTiO₃. Information on defects and strain states was obtained for a few graphene/SrTiO₃ samples that were synthesized by different techniques. This confocal Raman spectroscopic approach can shed light on the investigation of not only this graphene/SrTiO₃ system but also various two-dimensional layered materials whose Raman modes interfere with their substrates. [ABSTRACT FROM AUTHOR]