Vertical Liquid Crystal Orientation on Amorphous Tantalum Pentoxide Surfaces Depending on Anisotropic Dipole–Dipole Interaction via Ion Beam Irradiation

We achieved vertically aligned (VA) liquid crystals (LCs) on amorphous tantalum pentoxide (Ta 2 O 5 ) alignment films deposited by radio frequency (rf) magnetron sputtering using ion beam (IB) irradiation. By analyzing measurements by X-ray photoelectron spectroscopy (XPS), we confirmed the bond breaking, as detected from the O 1s spectra, which caused an isotropic dipole–dipole interaction between the LC molecules and the Ta 2 O 5 alignment film to uniformly align the vertical LC molecular orientation as a function of IB energy density. Moreover, by examining the electro-optical (EO) characteristics of the Ta 2 O 5 surfaces compared with those of the polyimide (PI) alignment layer, we confirmed that Ta 2 O 5 has a low threshold voltage and a low power consumption when used as an LC alignment layer.