Effect of oxygen plasma treatment on reduction of contact resistivity at pentacene/Au interface

We report the reduction of contact resistivity between Au and pentacene by O-2 plasma treatment. Contact resistance dramatically reduced from 5.65 to 0.22 M Omega cm by the treatment. O-2 plasma treatment transformed Au to AuOx, increasing the surface energy from 45.1 to 71.5 mJ/m(2). Molecular adsorption geometry of pentacene on AuOx changed from a planar structure to an upright type, improving crystallinity and molecular packing. Thus, defects and traps at the interface were reduced, decreasing the contact resistance between Au and pentacene.