Pentacene-Based Thin-Film Transistors With a Solution-Process Hafnium Oxide Insulator

Pentacene-based organic thin-film transistors with solution-process hafnium oxide (HfO x ) as gate insulating layer have been demonstrated. The solution-process HfO x could not only exhibit a high-permittivity (kappa = 11) dielectric constant but also has good dielectric strength. Moreover, the root-mean-square surface roughness and surface energy (gamma s ) on the surface of the HfO x layer were 1.304 nm and 34.24 mJ/cm 2 , respectively. The smooth, as well as hydrophobic, surface of HfO x could facilitate the direct deposition of the pentacene film without an additional polymer treatment layer, leading to a high field-effect mobility of 3.8 cm 2 /(V middots) .