Detection of polar chemical vapors using epitaxial graphene grown on SiC (0001)

VK Nagareddy, HK Chan, SC Hernandez, VD Wheeler, RL Myers-Ward, LO Nyakiti, CR Eddy Jr, SG Walton, JP Goss, NG Wright, DK Gaskill and AB Horsfall
Applied Physics Letters

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 carrier density induced by vapor molecules adsorbed on the surface of the graphene.

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