Ultrathin Poly(4-vinylphenol) Interfacial Layer Evaporation for Low-Voltage Operation of Organic Field-Effect Transistors with HfO2 Gate Insulator

Abstract

Ultrathin poly(4-vinylphenol) (PVP) layer formation by evaporation was investigated for the first time to improve the pentacene/HfO2 interface characteristics in bottom-gate organic field-effect transistors (OFETs). 3–10-nm-thick PVP layers were successfully deposited by evaporation. It was found that the surface roughness of the PVP layer was remarkably decreased at the deposition temperatures of 50–100 °C both on SiO2 and HfO2 gate insulators. The obtained relative dielectric constants of the PVP layers deposited on SiO2 and HfO2 were 3.4 and 4.8, respectively. The mobility in the fabricated pentacene-based p-type OFETs with the HfO2 gate insulator was increased from 0.25 cm2 to 0.32 cm2 V-1 s-1 at the operation voltage of 2 V by the 5-nm-thick PVP interfacial layer deposited at 50 °C.