Title:
Detection of Individual CO₂ Molecular Adsorption with Suspended Graphene in an Electrical Field

Speaker:
Jian Sun, Ph.D.
School of Materials Science, JAIST

Abstract:
We report the detection of individual carbon dioxide molecular physisorption with suspended graphene. A novel device design with inducing a large strain in graphene can prevent the collapsing of graphene onto substrate even with a high gate voltage. Thus electrical field can be introduced by back-gate voltage to accelerate the adsorption rates. The step-like resistance changes with a quantized value of 62 Ω, that is about 0.56% of the background resistance, are measured in the graphene upon exposure to low concentration CO₂ molecules; the discrete response observed is a clear evidence implying an individual adsorption event. Late theoretical first principle calculations suggest the similar resistance increment value for graphene after single adsorption, by considering the adsorbed molecules induced Coulomb impurity scattering.