<div>Metal oxides have been investigated for use in displays and wearable electronics, owing to their high mobility in the amorphous state. In solution-processed oxide thin-film transistors, post-deposition thermal processing significantly change the film’s transport properties, and is essential for high-performance devices. The mobility, bias stability and trapping-detrapping related hysteresis are improved with higher processing temperatures, which is generally attributed to decreased localized states which act as electron traps. Here we develop a model to validate that post-deposition processing indeed changes the density and properties of the localized states. We obtain good agreement between this model and the experimental data measured from sol-gel indium zinc oxide TFTs. When the processing temperature increases from 300 to 500 ⁰C, the model indicates that the trap state density in the bulk semiconductor and at the interface decrease by a factor of 5 and a factor of 3, respectively. Furthermore, the localized states become shallower, and the band mobility increases at higher processing temperatures.</div>

In solution-processed oxide thin-film transistors, post-deposition thermal processing significantly changes the film's transport properties and is essential for high-performance devices. The mobility, bias stability and trapping-detrapping related hysteresis are improved with higher processing temperatures, which is generally attributed to decreased concentrations of localized states that act as electron traps. Fabricating and characterizing 29 devices, we provide further experimental evidence that post-deposition processing indeed leads to enhanced channel electron mobility in sol-gel indium zinc oxide TFTs, and, on the basis of a simple model, we extract physical parameters that yield a quantitative assessment of the changes in the densities and the properties of the localized trap states. The data is obtained for sol-gel indium zinc oxide thin films and TFTs subjected to thermal postdeposition processing from 300 to 500 0 C. The extracted parameters indicate that the trap state density in the bulk semiconductor and at the interface decrease by factors of 5 and 3, respectively. Furthermore, the localized states become shallower, and the band mobility increases with higher processing temperatures.