Amorphous oxide thin-film transistors and inverters enabled by solution-processed multi-layers as active channels

This paper reports an indium zinc oxide (IZO) thin film transistor (TFT) with a multi-stacked structure that showed improved performance compared to the TFT with a single active-layer structure. Devices with a multi-stacked active-layer structure were fabricated using an IZO solution process. The determination results showed that the electrical operation and environmental stability of multi-stacked IZO TFTs were improved significantly compared to those of single active-layer IZO TFTs. The roughness of the device surface was measured by atomic force microscopy. The root mean square calculation showed that the multi-stacked active-layer IZO TFT had a smoother surface. The multi-stack structured IZO TFT showed an exceptional electron mobility of 7.75 ± 0.2 cm2/V s, an on–off current ratio of 4.67 × 105 ± 0.55 × 105, and a subthreshold swing of 1.11 V/decade. In addition, a weak threshold voltage (0.35 ± 0.42 V) that is more conducive to device driving was obtained. These results highlight the great potential of multi-stack structured IZO TFTs for applications in active-matrix backplane displays.