Development of High Performance Solution-Processed Oxide Thin-Film Transistors through Alkali Metal Doping and Dielectric Engineering

Abstract

Solution-processed oxide semiconductors thin-film transistors (TFTs) with transparent, flexible properties and low-cost manufacturing have a great potential for future display requiring advanced performances such as high resolution and large scale as well as unique properties such as transparency and flexibility. However, there are several limitations for practical applications. Especially, a relatively low field-effect mobility compared with that of low temperature poly Si (LTPS) TFTs and high vacuum-processed oxide semiconductor TFTs is a critical issue. Accordingly, many studies have mainly focused on the development of solution-processed oxide semiconductor TFTs having a high field-effect mobility with various methods. However, their low field-effect mobility still remains a problem. Herein, I propose alkali metal doping and dielectric engineering for the increase of field-effect mobility in solution-processed oxide semiconductor TFTs. Through alkali metal doping, the field-effect mobility of solution-processed ZnSnxOy (ZTO) TFTs was increased 2 ∼ 3 times. Also, with the dielectric engineering, the field-effect mobility of the ZTO TFTs could be dramatically enhanced. Using various analyses with X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray photoemission spectroscopy (XPS), developed TFT model, and the like, the mechanism how field-effect mobility is increased by the alkali metal doping and the dielectric engineering has been investigated. These methods have good potential for the application of the solution-processed oxide semiconductor in future display technology.