Molecular Adsorption Behavior of Epitaxial Graphene Grown on 6H-SiC Faces

Epitaxial graphene layers grown on 6H-SiC faces were investigated for molecular adsorption by electron withdrawing NO(2) and electron donating NH(3). 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. (C) 2010 The Japan Society of Applied Physics