Top-gate LZTO thin-film transistors with PMMA gate insulator by solution process

Top-gate thin-film transistors (TFTs) with indium-free multicomponent amorphous lanthanum-zinc-tin-oxide (a-LZTO) as channel layer and organic poly (methylmethacrylate) (PMMA) as dielectric layer were prepared by the solution process of the dip coating method. X-ray photoelectron spectroscopy (XPS) verified that the oxygen-vacancy–related O1 s peak decreased with increasing La content. Moreover, the addition of La 3+ caused the band gap of LZTO films to broaden. The results indicate that La atoms acted as a carrier suppressor in ZTO films. The optimum TFT performance was achieved at a La content of 9%, with saturated mobility of 3.07 cm 2 /Vs, threshold voltage of 0.89 V and on-to-off current ratio of ∼10 4 , respectively.