  Graphene layers placed on SrTiO3 single-crystal substrates were investigated
using temperature-dependent confocal Raman spectroscopy. This approach
successfully resolved distinct Raman modes of graphene that are often
untraceable in conventional measurements 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.
