Vertically Aligned Liquid Crystals on Tantalum Oxide Thin Films Using Ion Beam Irradiation Processing

Abstract

In this study, we explored the effects of ion beam (IB) bombardment on the orientation of liquid crystal (LC) molecules on Ta2O5 surfaces. Increasing the IB exposure time resulted in improved LC alignment characteristics. Through X-ray photoelectron spectroscopy analysis, it was also confirmed that IB irradiation caused Ta 4f and O 1s peak shifts in the positive direction. The breaking phenomenon of the O 1s bonds may cause anisotropic dipole-dipole forces to stably align the vertical LC molecules. Finally, measuring the contact angles on the IB irradiated Ta2O5 surfaces, we concluded that increasing the IB irradiation time strengthened the anisotropic surface energy on the Ta2O5 surfaces, and stable vertical LC alignment was achieved via the transformed surface energies.