Achieving High-Performance Solution-Processed Thin-Film Transistors by Doping Strong Reducibility Element Into Indium-Zinc-Oxide

Abstract

Adding an appropriate amount of suitable elements is an effective way to suppress In-Zn-O (IZO) carriers. The influence of different doping concentration Ca incorporation on In-Zn-O oxide-based thin film transistors (Ca-IZO TFTs) was investigated theoretically and experimentally. First-principles calculations show that as the doping concentration of Ca increases, the IZO bandgap gradually widens. Moreover, low-concentration doping of Ca does not significantly reduce carrier density and mobility. A novel high-performance Ca-IZO film has been experimented by a low-cost sol-gel process. And the best Ca-IZO TFT device was achieved when the mole ratio of Ca was 3%. The slight Ca-doped In-Zn-O TFT showed a high on/off current ratio ~106, a high field-effect saturated mobility of 1.4 cm2/Vs, and a positive threshold voltage $(V_{\mathrm{ th}})$ of 7.7 V.

Keywords

• Thin films transistors
• first-principles
• InZnO
• semiconductors
• solution-processed
• mobility