Low Temperature Combustion Processed Stable Al Doped ZnO Thin Film Transistor: Process Extendable up to Flexible Devices

Abstract

We report combustion synthesis of polycrystalline Aluminium doped zinc oxide (AZO) at low temperature for next generation low cost, flexible thin film transistor (TFT) application. Solution processed AZO thin film has been characterized by X ray diffraction and atomic force microscopy to confirm crystallinity. In this research work TFT with solution processed AZO as channel layer has been fabricated on both rigid and flexible substrate which exhibits excellent electrical stability and improved field effect mobility of 1.2 cm²V^-1S^-1, threshold voltage of 15 V and on-off ratio of 10⁶as compared to pure ZnO based TFT. All the measurements have been carried out with varying Al concentration. Moreover, variation in defect density of AZO with Al concentration which essentially causes significant change in TFT’s performance is demonstrated by chemical composition and bonding state analysis using XPS. Our results suggest that low temperature solution processed AZO TFTs have a potential for low cost, flexible and transparent electronic applications.