Comparative Study on Gate Insulators of Polymers and SiO_2 in Transport Properties of p- and n-Type Organic Field-Effect Transistors

摘要

Field-effect mobilities and threshold voltages in organic field-effect transistors (OFETs) were studied to elucidate the difference of the OFETs performance between Si/SiO_2 and flexible polymer substrates. The polymer OFETs were built on poly(ethylene naphthalate) (PEN) film as the substrate with polyimide (PI) as the gate-insulators. Pentacene and N,N'-ditridecytperylene-3,4,9,10-tetracarboxylicdiimide (PTCDI-C_(13)) were employed as p- and n-type semiconductors. The n-type OFET on polymer substrates exhibited higher electron mobility and smaller threshold voltages compared with those on Si/SiOj. On the contrary, the p-type OFET on the Si/SiO_2 substrate showed better transport performance than that on the polymer substrate. The results are discussed taking the difference of surface potential between SiO_2 and PI gate-insulator, which possibly modifies OFET characteristics.