In this work, we investigate an fabricating route of solution-processed thin-film transistors (TFTs). The high-k dielectric layers of aluminum oxide (AlO) were optimized through hydrogen peroxide (H₂O₂). With Zn incorporation in tin oxide (SnO) semiconductor layer, the ZnSnO TFT with a field effect mobility of 4.3 cm²·V^-1·s^-1, a threshold voltage of 2 V, a subthreshold swing of 0.16 V/dec and an on/off ratio of 10⁶.