Abstract
Epitaxial graphene layers grown on 6H-SiC faces were investigated for molecular adsorption by electron withdrawing NO2 and electron donating NH3. From amperometric measurements performed on these samples, we observed that epitaxial graphene grown on C-face SiC mostly behaved as a p-type sensing layer in contrast to the Si-face graphene, which behaved as n-type. Potentiometric sensing experiments performed reveal that epitaxial graphene on both C- and Si-faces have similar charge transfer mechanism with respect to a specific adsorbent gas.