Effective Atmospheric-Pressure Plasma Treatment toward High-Performance Solution-Processed Oxide Thin-Film Transistors

Solution-processed oxide semiconductors (OSs) have attracted much attention because they can simply, quickly, and cheaply produce transparent channels on flexible substrates. However, despite such advantages, in the fabrication process of OS thin-film transistors (TFTs) using the solution process, it is a fatal problem that there are hardly any ways to simply and effectively control important TFT parameters, including the turn-on voltage (V on) and on/off current ratio. For the practical application of solution-processed OS TFT, approaches to simply and effectively control the parameters are urgently required. Here, we newly propose an atmospheric-pressure plasma (APP) treatment that can simply and effectively control the electrical properties in solution-processed InO x TFTs. Through exposure of APP, we successfully realized the changes in important TFT parameters of solution-processed InO x TFT, V on from −11.4 to −1.9 V and the on/off current ratio from ∼103 to ∼106, which still keep up the high field-effect mobility (>20 cm2 V–1 s–1). On the basis of various analyses such as X-ray-based analysis and UV–visible spectroscopy, we identified that the APP treatment can effectively control oxygen vacancy and carrier concentration in solution-processed OS.