Liquid Crystal Alignment Capabilities on a New Diamond-Like Carbon Thin Film Layer

Hwang, Jeoung Yeon; Jo, Yong Min; Seo, Dae Shik; Rho, Soon Joon; Lee, Dae Kyu; Baik, Hong Koo

doi:10.1143/jjap.41.l654

Cited by 32 publications

(16 citation statements)

References 5 publications

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“…The NDLC thin film was deposited for 30 seconds when the portions of C 2 H 2 =He=N 2 gas is 3=0=30 at the PECVD. The LC pretilt angle has irradiation time over 2 minutes [18,19]. Ion-beam irradiation contributes to the generation of the pretilt angle and that value of the pretilt angle is more affected by surface roughness than sp 2 -fraction of the NDLC thin films.…”

Section: Methodsmentioning

confidence: 99%

The Alignment Effect of Nematic Liquid Crystal on NDLC Thin Films Surface

Park

Kang

Hwang

et al. 2005

Molecular Crystals and Liquid Crystals

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We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of Nitrogen doped diamond-like carbon (NDLC) thin film. The NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about 9.9 by ion beam (IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin film surface at annealing temperature of 200 C. The alignment defect of the NLC was observed above annealing temperature of 250 C. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.

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Section: Methodsmentioning

confidence: 99%

The Alignment Effect of Nematic Liquid Crystal on NDLC Thin Films Surface

Park

Kang

Hwang

et al. 2005

Molecular Crystals and Liquid Crystals

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“…This situation stimulates development of alternative alignment methods. Recent years were marked by the great interest to so called ion= plasma beam alignment, which has shown high efficiency for LCs [1][2][3][4][5][6][7][8] and reactive mesogens [9]. The essence of the method is that surfaces treated by ion or plasma beams from oblique angle develop an ability to align LCs.…”

Section: Introductionmentioning

confidence: 99%

Plasma Beam Alignment of Liquid Crystals on the Bare Glass: Modification of Surface Chemical Composition

Kravchuk

Artyushkova

Yaroshchuk

2011

Molecular Crystals and Liquid Crystals

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X-ray Photoelectron Spectroscopy was applied to study the chemical composition of the modified glass surfaces by the flux of accelerated Ar or Ar=H 2 plasma in order to clarify mechanisms of liquid crystal (LC) alignment on these surfaces. It was established that the surface of prinstine glass exposed to air contains carbonaceous contamination layer consisting of about 50% of aliphatic=aromatic carbon and about 50% of C-O moieties of various types. Plasma processing results in partial ablation of this layer and modification of its chemical composition. This suggests that LCs are actually being aligned by the plasma modified carbonaceous layer rather than by a pure glass.

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“…As an alternative, the uniform alignment of a LC has been attempted recently by non-contact alignment methods using ultraviolet (UV) or ion-beam (IB) exposure to inorganic substrates [4]. Since LC alignment by IB exposure of diamond like carbon (DLC) thin films was first reported [5], comprehensive studies have been focused on DLC thin films as inorganic layers for LC alignment [6,7]. Stohr et al reported that LC molecules could be aligned on IB-irradiated DLC films due to carbon cluster rings or benzene rings [5].…”

Section: Introductionmentioning

confidence: 99%

Effects of plasma treatments on correlation between chemical structures of DLC films and liquid crystal alignment

Choi

Ham

et al. 2006

Liquid Crystals

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In an effort to obtain an improved liquid crystal (LC) alignment layer for liquid crystal display device applications, amorphous diamond-like carbon thin films were deposited on ITO-coated glass substrates by an rf magnetron sputtering technique at room temperature and then treated with plasma in various atmospheres. The polarized images and pretilt angles of the LC cells showed that LC alignment was enhanced by post-plasma treatments of the films. In Raman and X-ray photoelectron spectroscopy spectra of the films, an increase in the fraction of sp 2 -bonding was observed after post-plasma treatments of the films. In particular, H 2 plasma-treated film had the largest fraction of sp 2 -bonding at the film surface and showed much improved alignment capabilities. These results suggest that p-bondings of the sp 2 -structure at the surface rather than the bulk play an important role in LC alignment.

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Liquid Crystal Alignment Capabilities on a New Diamond-Like Carbon Thin Film Layer

Cited by 32 publications

References 5 publications

The Alignment Effect of Nematic Liquid Crystal on NDLC Thin Films Surface

The Alignment Effect of Nematic Liquid Crystal on NDLC Thin Films Surface

Plasma Beam Alignment of Liquid Crystals on the Bare Glass: Modification of Surface Chemical Composition

Effects of plasma treatments on correlation between chemical structures of DLC films and liquid crystal alignment

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