Preparation and characterization of micro-grid modified In2O3:W films

• In2O3:W (IWO) films were obtained by reactive frequency magnetron sputtering.
• IWO micro-grids were prepared on the surface of IWO films.
• Influences of micro-grid size and sputtering time on IWO films were analyzed.
• Both high conductivity and transparency are acquired in near-infrared region.

Tungsten doped indium oxide (In2O3:W, IWO) thin films with IWO micro-grid covered surface were prepared at room temperature using techniques of radio frequency (RF) magnetron sputtering and polystyrene (PS) microsphere template. The composition, crystallization structures, surface morphologies, and optical and electrical properties of the films were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, spectrophotometer from visible to near infrared (NIR) range and Hall effect measurement, respectively. Periodic micro-grid modified surface was obtained to improve light trapping properties. The effects of the PS micro-spheres diameters and the sputtering time on the surface morphology, transmittance in NIR range, diffuse reflection and conductive properties of the IWO films are investigated. Experiments show that surface modification of the IWO film with micro-grid under the optimized condition can improve the conductivity of the films by 15%, and the diffuse reflectance by 150%, with less than 8% decrease of the transmittance in the visible region. The study would be beneficial to the light trapping effect of solar cells using IWO films as transparent electrodes.