Effects of annealing on the characteristics of ZnO films deposited in various O2/（O2＋Ar） ratios

C-axis oriented ZnO films are deposited on polished diamond substrates in various O2/（O2＋Ar） ratios using the radio frequency（RF） magnetron sputtering technique and are subsequently annealed in oxygen ambience under the same conditions.Structural,morphologic and electrical properties of ZnO films are characterized by X-ray diffraction（XRD）,high-resistance instrument,energy dispersive X-ray spectroscopy（EDS） and scanning electronic microscopy（SEM）.As the O2/（O2＋Ar） ratio increasing from 1/12 to 5/12,the crystallinity of the as grown ZnO films becomes better and the electrical resistivity increases slowly.After annealing,the ZnO films deposited in O2/（O2＋Ar） =1/12 and 3/12 are improved greatly in crystallinity,and their electrical resistivity is enhanced by two orders of magnitude,while those deposited in O2/（O2＋Ar） =5/12 are scarcely changed in crystallinity,and their resistivity is only increased by one order.In addition,the ZnO films deposited in O2/（O2＋Ar） =3/12 and annealed in oxygen are with the best crystal quality and the highest resistivity.