Surface potential of pentacene films and contact metallurgy for organic-based electronic applications

We investigated surface potential profiles for pentacene films as a function of the film thickness and the contact metallurgy (Au and Al) by using a near-field microwave microprobe analysis and Kelvin-probe force microscopy. The surface potential for the Al/pentacene bilayers increased monotonically with the thickness of pentacene while no thickness dependence of the surface potential was for the Au/pentacene bilayers. These results are discussed based on the potential barrier at the metal/pentacene interface due to the space charge.