Multiple ink-jet printed zinc tin oxide layers with improved TFT performance

In the last two decades, metal-oxides, like zinc tin oxide (ZTO), are widely studied semiconductors for transistor applications. This study presents a simple, non-toxic, stable, and cost efficient precursor route for ZTO deposition by ink-jet printing. Such fabricated thin films are composed of an amorphous phase with embedded ZnO nanocrystals. The saturation mobility of ink-jet printed transistors increases from 0.05 cm(2) V-1 s(-1) for a single semiconducting layer to 7.8 cm(2) V-1 s(-1) for a transistor composed of 8 layers. This constitutes the highest saturation mobility of an ink-jet printed ZTO transistor reported so far. The devices exhibit large output currents (up to 38.7 mA) and high on/off ratios (exceeding 10 8). The large improvement in transistor performance with the number of layers is ascribed to an improved degree of substrate coverage confirmed by AFM investigations. Published by AIP Publishing.