New transparent conducting MgIn2O4-Zn2In2O5 thin films prepared by magnetron sputtering

New materials for a transparent conducting oxide film are demonstrated. Highly transparent Zn2In2O5 films with a resistivity of 3.9X10(-4) Omega cm were prepared on substrates at room temperature using a pseudobinary compound powder target composed of ZnO (50 mol.%) and In2O3 (50 mol.%) by r.f. magnetron sputtering. MgIn2O4-Zn2In2O5 films were prepared using MgIn2O4 targets with a ZnO content of 0-100 wt.%. The resistivity of the deposited films gradually decreased from 2X10(-3) to 3.9X10(-4) Omega cm as the Zn/(Mg+Zn) atomic ratio introduced into the films was increased. The greatest transparency was obtained in a MgIn2O4 film. The optical absorption edge of the films decreased as the Zn/(Mg+Zn) atomic ratio was increased, corresponding to the bandgap energy of their materials. It was found that the resistance of the undoped Zn2In2O5 films was more stable than either the undoped MgIn2O4, ZnO or In2O3 films in oxidizing environments at high temperatures.