Impact of oxygen plasma treatment on carrier transport and molecular adsorption in graphene

Impact of plasma treatment on graphene's transport properties and interaction with gas molecules has been investigated with Raman, X-ray photoelectron spectroscopy, and Hall measurements. Experimental results indicate the formation of nanocrystalline domains and the enhanced fraction of adsorbed oxygen following oxygen plasma treatment, which correlates with a significant reduction in carrier mobility and an increase in carrier density. The oxygen plasma treated graphene was found to exhibit much stronger sensitivity toward NH3 molecules both in terms of magnitude and response rate, attributable to increased domain edges and oxygen adsorption related enhancement in p-type doping. The carrier mobility in plasma exposed graphene was modeled considering both ionized impurity and short-range scattering, which matched well with the experimentally observed mobility.