Effect of Film Thickness on the Properties of Transparent Conductive Mn-W Co-doped Zinc Oxide Films

Highly conductive and transparent Mn-W co-doped ZnO(ZMWO) thin films were deposited on low-temperature glass substrate by DC magnetron sputtering.The effect of film thickness on structure,optical and electrical properties were studied.The X-ray diffraction results show that all the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate.The crystallinity,resistivity as well as sheet resistance of ZMWO films largely depend on film thickness.As the film thickness increases from 97 nm to 456 nm,the crystallinity of the film increases obviously while the resistivity and sheet resistance decreases.The deposited film with an electrical resistivity as low as 8.8×10-5 Ω·cm,a small sheet resistance of 1.9 Ω/□ was obtained at film thickness of 456 nm.All the deposited films show a high average transmittance of about 89% in the visible range.However,the optical band-gap increases from 3.41 eV to 3.52 eV as film thickness increases from 97 nm to 456 nm.