In this paper, we study the Ion-beam (IB) irradiated amorphous (a)-aluminum oxide (${\hbox{Al}}_{2} {\hbox{O}} _{3}$) inorganic layer deposited by RF magnetron sputtering as an liquid crystal (LC) alignment layer. Uniformly vertical-aligned (VA)-LC on a-${\hbox{Al}}_{2} {\hbox{O}} _{3}$ surface resulted from IB irradiation energy above 1800 eV. We assumed that LC molecular orientation depends on the intensity of Al 2p, O 1s peaks, which were confirmed through X-ray photoelectron spectroscopy (XPS) measurements. XPS showed that IB irradiation changed the chemical structure, breaking Al-O bonds by altering Al–O and O–Al bonding intensity. Also, electro-optical characteristics of vertical-aligned-LC displays (VA-LCDs) on the ${\hbox{Al}}_{2} {\hbox{O}} _{3}$ alignment layers were measured, which showed reduced threshold voltage and power consumption, as compared with IB irradiated and rubbed polyimide (PI) layers.