Effects of composition on optical and electrical properties of amorphous In-Ga-Zn-O films deposited using radio-frequency sputtering with varying O2 gas flows

► Amorphous In-Ga-Zn-O (a-IGZO) films deposited using radio frequency sputtering. ► Average transmittance of zinc-rich a-IGZO films over 80% in various O2 flows. ► Average transmittance of zinc-less a-IGZO film without O2 flow decreased below 10%. ► In and In2O3 crystalline precipitation can lower transmittance in In-rich a-IGZO films. ► a-IGZO resistivity increased with Ga content increase and In content decrease.