Large-area (64 × 64 array) inkjet-printed high-performance metal oxide bilayer heterojunction thin film transistors and n-metal-oxide-semiconductor (NMOS) inverters

Abstract

It is a big challenge to construct large-scale, high-resolution and high-performance inkjet-printed metal oxide thin film transistor (TFT) arrays with independent gates for the new printed displays. Here, a self-confined inkjet printing technology has been developed to construct large-area (64 × 64 array), high-resolution and high-performance metal oxide bilayer (In2O3/IGZO) heterojunction TFTs with independent bottom gates on transparent glass substrates. Inkjet printing In2O3 dot arrays with the diameters from 55 to 70 μm and the thickness of ∼10 nm were firstly deposited on UV/ozone treated AlOx dielectric layers, and then IGZO dots were selectively printed on the top of In2O3 dots by self-confined technology to form In2O3/IGZO heterojunction channels. When the inkjet-printed IO layers treated by UV/ozone for more than 30 min or oxygen plasma for 5 min prior to print IGZO thin films, the mobility of the resulting printed In2O3/IGZO heterojunction TFTs are correspondingly enhanced to be 18.80 and 28.44 cm2 V−1 s−1 with excellent on/off ratios (>108) and negligible hysteresis. Furthermore, the printed N-Metal-Oxide-Semiconductor (NMOS) inverter consisted of an In2O3/IGZO TFT and an IGZO TFT has been demonstrated, which show excellent performance with the voltage gain up to 112. The strategy demonstrated here can be considered as general approaches to realize a new generation of high-performance printed logic gates, circuits and display driving circuits.