Solution processed amorphous gallium-incorporated tin oxide thin-film transistors

In this paper, we prepared amorphous gallium-incorporated tin oxide (a-SnGaO) thin-film transistors (TFTs) with respect to various Ga contents and annealing temperatures. All TFTs exhibit excellent switching characteristics. As the gallium content increases, the off-state current of the a-SnGaO TFTs decreases, the threshold voltage (V th) shifts towards positive voltage, and the subthreshold swing (S.S.) improves. The optimal gallium content is 20 at%, the corresponding saturation mobility of a-SnGaO TFTs is 5.2 cm2 V−1 s−1, the threshold voltage is −2.3 V, and the S.S. is 0.7 V dec.−1. The switching ratio is 1.5 × 106. Furthermore, we investigated the effect of annealing temperature on the electrical properties of a-SnGaO TFTs. It was found that as the annealing temperature increases, the mobility of a-SnGaO TFTs increases and the S.S. improves, which is greatly due to the increase of free electrons and reduction of defect states in the channel layer.