Epitaxial graphene grown on SiC (0001) showed significant changes in electrical resistance
upon exposure to polar protic and polar aprotic vapors in the ambient atmosphere. The
dipole moment of these chemicals was found to have a strong impact on the magnitude of
the sensor response, which increases with increasing dipole moment. Using the
combination of low-frequency noise and Hall measurements, we demonstrate that the
chemical sensing mechanism in epitaxial graphene is based on fluctuations of the charge …