Electrical transport properties of Al-doped ZnO films

► High quality Al:ZnO films were deposited by rf magnetron sputtering technique. ► Metal-semiconductor transition was found in Al:ZnO film with big grain size. ► Both 2% and 4% Al-doped ZnO films are intrinsic metal in electrical transport properties. ► The tunneling effect dominates the temperature behavior of resistivity of Al:ZnO film with small grain size.