Ambipolar organic thin-film transistors using $C60$/pentacene structure: Characterization of electronic structure and device property Available to Purchase

We fabricated ambipolar organic thin-film transistors (OTFTs) using $C60$ and pentacene. The electronic structure of the interface was investigated by using ultraviolet photoelectron spectroscopy and x-ray photoelectron spectroscopy. The magnitude of the interface dipole and the band bendings at the interface was determined, and the complete energy level diagram for $C60$ on pentacene (⁠$C60$/pentacene) was obtained. The lowered band offsets, due to the enhanced charge redistribution in $C60$/pentacene relative to pentacene on $C60$⁠, are favorable for the ambipolar OTFTs. The measured field-effect mobilities were $0.017cm2∕Vs$ and $0.007cm2∕Vs$ for the $p$-channel and the $n$-channel operations, respectively. The threshold voltages were $−2V$ for the $p$ channel and $15.6V$ for the $n$ channel, comparable to those of unipolar OTFTs using $C60$ or pentacene.