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

Journal Article · Sun Mar 01 04:00:00 EST 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3080159· OSTI ID:21190065

Oh, Byeong-Yun; Lee, Won-Kyu; Kim, Young-Hwan; Seo, Dae-Shik ^[1]

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1. Department of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

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 (1013) was observed with a tilt angle of approximately 28.1 deg. 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.

• OSTI ID: 21190065
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 5 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL BONDS
CRYSTAL GROWTH
DEPOSITION
ELECTRO-OPTICAL EFFECTS
ION BEAMS
LAYERS
LIQUID CRYSTALS
PHASE TRANSFORMATIONS
RADIOWAVE RADIATION
SEMICONDUCTOR MATERIALS
SPUTTERING
TEXTURE
THIN FILMS
VAN DER WAALS FORCES
ZINC OXIDES