High-performance solution processed oxide Thin Film Transistor with double-layered amorphous Aluminum Indium Zinc oxide

We investigated the performances of aluminum added indium zinc oxide (IZO) thin film transistors (TFTs) with solution process using double layers that consist of separated aluminum molar concentrations. Bottom gate thinfilm transistors were fabricated using solution-processed Al-IZO channel layers with various aluminum composition ratios. These Al-IZO thin films were annealed on a hot plate. Increasing the Al ratio from 0.05 to 0.5, with a fixed Zn: In ratio of 2: 3, induced a threshold voltage shift in the positive direction. Existing solution-processed IZO research shows that saturation mobility is between 0.5 and 2 cm(2)/V.s, but this paper shows that the electrical performances were greatly improved by varying the molar concentration of aluminum. The saturation mobility of the Al-IZO double layer TFT was increased to 7.75 cm(2)/V.s. X-ray Photoelectron Spectroscopy and X-ray Diffraction analyses of Al-IZO films were conducted to investigate the binding energies of atoms in Al-IZO films and the crystalline properties of the films.