Water-based processed and alkoxide-based processed indium oxide thin-film transistors at different annealing temperatures

In this study, indium oxide (In 2 O 3 ) thin-film transistors (TFTs) are fabricated by two kinds of low temperature solution-processed technologies ( ), i.e., water-based (DIW-based) process and alkoxide-based (2-ME-based) process. The thickness values, crystallization properties, chemical structures, surface roughness values, and optical properties of In 2 O 3 thin-films and the electrical characteristics of In 2 O 3 TFTs are studied at different annealing temperatures. Thermal annealing at higher temperature leads to an increase in the saturation mobility ( μ sat ) and a negative shift in the threshold voltage ( V TH ). The DIW-based processed In 2 O 3 -TFT annealed at 300 °C exhibits excellent device performance, and one annealed at 200 °C exhibits an acceptable μ sat of 0.86 cm 2 /V·s comparable to that of a-Si:H TFTs, whereas the 2-ME-based TFT annealed at 300 °C exhibits an abundant μ sat of 1.65 cm 2 /Vs and one annealed at 200 °C is inactive. The results are attributed to the fact that the DIW-based process induces a higher degree of oxidation and less defect states than the 2-ME-based process at the same temperature. The DIW-based process for fabricating the In 2 O 3 TFT opens the way for the development of nontoxic, low-cost, and low-temperature oxide electronics.