We investigate the effect of Ar/O-2 gas ratio on optical, structural and electrical properties of thin yttrium-doped In-Zn-O (YIZO) film. Thin YIZO films were deposited at room temperature on glass substrates by radio frequency magnetron co-sputtering system using IZO target composed of (In2O3)(1-x)(ZnO)(x) (x = 50 wt.%) and Y2O3. The measured average optical transmittance of as-grown YIZO films is over 84% in visible range. Structural analysis reveals that amorphous phase of YIZO is observed only in pure Ar gas flow condition, while crystalline peaks are found as the oxygen content in gas flow increases. Electrical resistivity of the films sharply increases with increasing Ar:O-2 ratio, however its carrier concentration and mobility decreases as the O-2 ratio increases. The drain-source on/off modulation from the fabricated YIZO Thin Film Transistors is over 10(6). (C) 2013 Elsevier B.V. All rights reserved.