Vertically aligned liquid crystal molecules on a silicon nitride film treated by ion-beam irradiation

Vertical alignment (VA) of a liquid crystal display (LCD) device with a stable pretilt angle has been achieved on ion-bombarded silicon nitride (SiN x) surfaces. The surface energy variation of the SiN x surface with the bonding conversion achieved via ion beam bombardment makes it possible to control the liquid crystal (LC) pretilt angle. X-ray photoelectron spectroscopy revealed that the vertical orientation of the LC molecules occurs on the SiO 2 surface and that this orientation is directionally transformed upon ion bombardment of SiN x thin films. Moreover, the upgraded electro-optical characteristics of VA-LCDs showed potential for high-performance LCD applications on modified SiN x surfaces.