Highly transparent conductive ZnO films prepared by reactive RF sputtering with Zn/ZnO composite target.

Using Zn/ZnO composite target, ZnO films were prepared by RF magnetron sputtering under Ar, Ar + O₂ and Ar + H₂ atmospheres and substrate temperatures of 150 and 300 °C. The effects of gas (O₂ or H₂) flow rate and substrate temperature on the thickness, preferred orientation, crystallinity, stress, transparent conductive properties, electrically conductive stability in air, E_g and Raman spectrum of the films were investigated. The results show that the film prepared in Ar atmosphere exhibits poor transparent conductive properties and conductive stability. Substrate temperature of 300 °C is advantageous to prepare ZnO films with (002) preferred orientation, high crystallinity, low compressive stress and good transparent conductive properties under Ar + O₂ atmosphere. Under Ar + H₂ atmosphere, ZnO films with low compressive stress and better transparent conductive properties can be obtained at substrate temperature of 150 °C. The related mechanisms for the effect of gas flow rate and substrate temperature on structure and properties of ZnO films are discussed. [ABSTRACT FROM AUTHOR]