Large Area, Ultrathin, and Transparent InGaZnO Films from Printing of Liquid Ga–In–Zn Alloys for Thin Film Transistors

Amorphous InGaZnO (IGZO) films with high visible transmittance and wide bandgaps are good candidates to fabricate thin film transistors' (TFTs) switching for flat-panel displays. The traditional sputtering and liquid solution deposition processes make it difficult to prepare ultrathin IGZO films with large area and low cost. Herein, we report a one-step printing process to successfully obtain centimeter scale, ultrathin, and low cost IGZO films by printing liquid Ga-In-Zn alloys. The printed IGZO films have near 100% transmittance of visible light and bandgaps above 4.17 eV. The printed IGZO films were further used to fabricate TFTs, which show n-type switching and display a good stability under visible light illumination. The fabricated TFTs show an on/off ratio above 10(3), a maximum field effect mobility of 14.25 cm(2) V-1 s(-1) and a minimum subthreshold swing of 0.46 V dec(-1). With the Ga2O(3) concentration in printed IGZO films increasing, the on/off ratios of TFTs increase, while the field effect mobility of TFTs decreases. This printing strategy provides a facile route to obtain IGZO nano films, which have great potentiality in fabricating high performance TFT switching for flat-panel displays.