Effects of polymer gate dielectrics roughness on pentacene field-effect transistors

The effects of the surface roughness of the polymer gate dielectrics on pentacene field-effect transistors were investigated. Using a poly(methylmethacrylate)/anodized Al2O3 dual-layer gate dielectric, the root-mean-square roughness of the gate dielectrics varied from 0.45 to 1.51 nm, independently of other gate dielectric properties such as the capacitance and surface energy. This range of root-mean-square roughnesses had little effect on the carrier mobility. X-ray diffraction analyses further revealed that the roughness of poly(methylmethacrylate) neither decreased the degree of crystallinity nor distorted the crystalline structure of pentacene.