Alignment of liquid crystal molecules on solution-derived zinc-tin-oxide films via ion beam irradiation

We present the characteristics of annealing temperature-dependent, zinc-tin-oxide (ZTO) films deposited by a solution process for application in liquid crystal displays (LCDs). ZTO surfaces supported homogeneously-aligned liquid crystal (LC) molecules based on an ion beam irradiation system. Uniform LC alignment and a precise pretilt angle were obtained at an annealing temperature greater than 300 °C. The oxidation of ZTO films was confirmed using field-emission-scanning electron microscopy and X-ray photoelectron spectroscopy. The electro-optical characteristics of electrically controlled birefringence (ECB) cells based on the ZTO films were superior to those based on polyimide. Especially, IB-irradiated ZTO films exhibited superior performance with respect to response time. This result indicates that this approach will allow for the fabrication of advanced LCDs with high performance.