Zinc oxide nanolevel surface transformation for liquid crystal orientation by ion bombardment

Byeong Yun Oh, Won Kyu Lee, Young Hwan Kim, Dae-Shik Seo

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22 Citations (Scopus)

Abstract

This paper introduces the characteristics of the zinc oxide (ZnO) inorganic film deposited by radio-frequency magnetron sputtering as an alternative alignment layer for liquid crystal display (LCD) applications. The crystalline structure related to the texture formation of ZnO (10 1- 3) was observed with a tilt angle of approximately 28.1° to the ZnO (0001) plane, leading to a smooth surface and high-density structure. Ion beam (IB) bombardment at various incident angles was used to induce liquid crystal (LC) alignment and cause the measured pretilt angle on ZnO films to assume a triangular contour. The orientation order of liquid crystal molecules was due to the van der Waals force for the vertical alignment of LCs with selective breaking of O-Zn bonds by IB bombardment. The contact angle contour as a function of the IB incident angle resembled the behavior of the pretilt angle. The pretilt angle is controllable by adjusting the surface features on ZnO films with IB bombardment. The electro-optic characteristics of vertically aligned (VA)-LCD based on ZnO film were comparable to those of VA-LCD based on polyimide, showing good potential of ZnO film as a LC alignment layer.

Original languageEnglish
Article number054506
JournalJournal of Applied Physics
Volume105
Issue number5
DOIs
Publication statusPublished - 2009 Mar 24

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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