Thin film transistors with ink-jet printed amorphous oxide semiconductors

We investigated the influence of the thickness of printed Ga-In-Zn-O (GIZO) channel on transistor performance. Semiconductor layers were inkjet printed using sol-gel derived GIZO solution and the thickness of the resulting active layers varied depending on the pre-heated substrate temperature. We found that GIZO film thickness significantly influences device performance. Thin film transistors (TFTs) with thicker active layers showed higher on-current/off- current mobility and a threshold voltage shift in the negative direction. The dependence of the electric characteristics on thickness resulted from the increased intrinsic free charge carriers as the active layer thickness increased. Ink-jet printing conditions need to be carefully controlled to maximize device performance.