Comproportionation Reaction Synthesis to Realize High-Performance Water-Induced Metal-Oxide Thin-Film Transistors

Solution-processed metal-oxide thin films have been widely studied in low-power and flexible electronics. However, the high temperature required to form a condensed and uniform film limits their applications in flexible and low-cost electronics. Here, a novel and environmental-friendly comproportionation reaction synthesis (CRS) is presented to obtain amorphous aluminum oxide (AlO_x) thin films for solution-processed thin-film transistors (TFTs) employing water as the precursor solvent. The thermal decomposition of CRS-AlO_x precursor is completed at ≈300 °C, which is 100 °C lower than that of the conventional water-induced AlO_x. The morphological, optical, compositional, and electrical properties of CRS-AlO_x dielectric films are studied systematically. Meanwhile, TFTs based on water-induced In₂O₃ metal oxide semiconductor layers deposited on these dielectrics at low temperatures are formed and characterized. Compared with TFTs based on conventional AlO_x showing low mobility and low clockwise hysteresis, In₂O₃ TFTs based on CRS-AlO_x exhibit improved electrical performance and counterclockwise hysteresis in the transfer curves. Water-induced TFTs fabricated on CRS-AlO_x formed at a low temperature of 250 °C have average mobility of 98 cm² V⁻¹ s⁻¹. Through chemical composition characterization and electrical characterization, the high mobilities of TFTs based on CRS-AlO_x dielectrics are correlated to trap states, which resulted in counterclockwise hysteresis in the transfer curves.