Optical-power-dependent photodesorption kinetics of graphene studied by conductance response

Abstract

The photodesorption kinetics of graphene with various UV laser power is studied by conductance response. Analytical expressions of the power-dependent photodesorption kinetics of graphene in ambience are derived. The photodesorption time constant tau(d), steady current, and magnitude of modulation current, can be expressed as functions of the adsorption time constant tau(a), desorption cross section sigma, and photon flux density. Under illumination the steady occupation ratio of adsorbed O-2 on graphene is equal to tau(d)/tau(a). It is suggested that the photodesorption of O-2 on graphene is attributed the injection of photogenerated hot electrons and is restricted by the density of antibonding states of O-2. (C) 2015 Optical Society of America