Electrical control of nanoscale functionalization in graphene by the scanning probe technique

Attaching atoms, such as oxygen and hydrogen, to graphene alters its conductivity and introduces semiconducting bandgaps — a valuable trick for researchers seeking to fine-tune the electrical behavior of this ultrathin material. But achieving nanoscale control over graphene's surface chemistry is challenging; conventional lithographic patterning leaves behind charge scattering centers that can upset device performance. Bae Ho Park from Konkuk University in South Korea and co-workers have discovered a way to ‘draw’ atomically defined circuit patterns on graphene using a conductive atomic force microscope (AFM). By applying either a positive or negative voltage to graphene samples, the team selectively generated small-scale regions of surface oxygen or hydrogen atoms with the scanning AFM tip. Intriguingly, this method yields functional group coverage close to the theoretical maximum — a significant improvement over existing methods.