Phosphonic acid self-assembled monolayer improved the properties of n-type organic field-effect transistors in air ambient†
Abstract
Here we report an approach to surface modification of the SiO2 gate dielectric on a Si device based on a simple procedure in which a dilute solution of a phosphonic acid is drawn down across the surface of the Si substrate. A crystalline thin film of NDI-C14 was successfully grown by vapor deposition on the surface of SAM modified dielectrics and obtained improved electron mobility up to 4.23 × 10−2 cm2 V−1 s−1 at room temperature in air ambient. Three SAM (ODPA, TDPA, and NAPA) modified dielectrics increased the electron mobility of the NDI-C14 by three orders of magnitude compared to that on bare SiO2. The improvement of electron mobility is associated with the close packing arrangement of NDI-C14 film on different SAMs.