Thin-film transistors (TFTs) with aluminum indium oxide channel layers were fabricated via a simple and low cost solution process. The substitution of Al on In sites in the In(2)O(3) lattice was verified by X-ray diffraction analysis. The maximum heat-treatment temperature of these transistors was 350 degrees C, and the resultant thin films were highly transparent (with >90% transmittance). The fabricated TFTs operated in an enhancement mode on a positive bias and showed an n-type semiconductor behavior. They exhibited a channel mobility of 19.6 cm(2)/V s, a subthreshold slope of 0.3 V/decade, and an on-to-off current ratio greater than 10(8).