A high mobility C₆₀ field-effect transistor with an ultrathin pentacene passivation layer and bathophenanthroline/metal bilayer electrodes

C₆₀ field-effect transistor (OFET) with a mobility as high as 5.17 cm²/V·s is fabricated. In our experiment, an ultrathin pentacene passivation layer on poly-(methyl methacrylate) (PMMA) insulator and a bathophenanthroline (Bphen)/Ag bilayer electrode are prepared. The OFET shows a significant enhancement of electron mobility compared with the corresponding device with a single PMMA insultor and an Ag electrode. By analysing the C₆₀ film with atomic force microscopy and X-ray diffraction techniques, it is shown that the pentacene passivation layer can contribute to C₆₀ film growth with the large grain size and significantly improve crystallinity. Moreover, the Bphen buffer layer can reduce the electron contact barrier from Ag electrodes to C₆₀ film efficiently.