High‐Performance Pentacene Organic Thin‐Film Transistor by Using Nd2O3 Gate Dielectric Doped with Nb

Abstract

Pentacene organic thin‐film transistors (OTFTs) using high‐k NdxNb(1−x)O gate dielectric with different Nb contents (x = 1, 0.950, 0.908, and 0.877) are fabricated. The best OTFT has x = 0.950, achieving a high carrier mobility of 1.95 cm2 V−1 s−1, small threshold voltage of −1.57 V, small sub‐threshold swing of 0.13 V dec−1, and small hysteresis of 0.13 V. Atomic force microscopy and X‐ray photoelectron spectroscopy measurements reveal that the Nb doping can suppress the hygroscopicity of Nd oxide to produce a smoother dielectric surface, on which larger pentacene grains are grown to result in higher carrier mobility. The hysteresis of the OTFTs is attributed to donor‐like traps associated with the hydroxide formed in Nd2O3 after absorbing moisture and also acceptor‐like traps (in the form of oxygen vacancies) induced by Nb incorporation.