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.