Effects of Gate Electron Concentration on Organic Thin-Film Transistors with Different Pentacene Thicknesses

Abstract

Bottom-gate pentacene organic thin-film transistors (OTFTs) with different gate electron concentrations and pentacene thicknesses are fabricated. The performances of the OTFTs show dependence on both gate electron concentration and pentacene thickness. Electrons in the gate electrode can reduce the effect from surface optical phonons of the high-k gate dielectric (NdTaON), and so higher gate electron concentration gives better device performance. It is also supported by measurements at 140°C, where the remote phonon scattering is enhanced. Moreover, it is found that the extracted carrier mobility decreases with increasing pentacene thickness, which is attributed to the series resistance of the source/drain electrodes.