Hydrogen mediated self-textured zinc oxide films for silicon thin film solar cells

In the present study, we introduce a method for preparing textured zinc oxide (ZnO) thin films by hydrogen associated magnetron sputtering. The improved surface morphology and structure characteristic indicate that hydrogen could efficiently mediate the crystal orientation by playing an important role in influencing the surface diffusion and sticking processes. This textured surface morphology leads to a high haze factor which provides effective light trapping efficiency. In addition, the electrical properties of ZnO films are also enhanced with high carrier concentration and mobility. Layers with comparable electrical (sheet resistance <5 Ω/sq), optical (average total transmittance >80% from 400 nm to 1200 nm) and morphological (RMS>50 nm) properties to Asahi U-type fluorine doped tin dioxide (FTO) have been obtained. Preliminary microcrystalline silicon solar cells deposited on self-textured ZnO show 13.2% and 20% enhancement in short-circuit current density and efficiency, respectively, illustrating a good potential application in mass production for large area expansibility.

► Self-textured ZnO thin films have been prepared by magnetron sputtering.
► Surface morphology and haze factor show its effective light trapping property.
► Structure characteristic is investigated to explore the texture formation reason.
► Electrical properties are improved with hydrogen mediation.
► μc-Si:H cells are deposited showing its good potential as front contact.