• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.288.2-288.2
• /
• 2014

InP quantum dots were grown by using the molecular beam epitaxy technique. Quantum dots are connected and composed string-like one-dimensional structure due to the strain field along [110] crystal direction. Two prominent photoluminescence transitions from normal quantum dots and string-like one-dimensional structure were observed which show strong optical anisotropy along [1-10] and [110] crystal directions. Both peaks also showed blue-shift while rotating emission polarization from [1-10] to [110] direction. Such optical transition behaviors are the consequence of the valence band mixing caused by strain field along the [110] crystal direction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.2
• /
• pp.174-179
• /
• 2005

We have designed a novel single cell gap transflective display associated with dual orientation of the liquid crystal. Owing to hybrid alignment in reflective part, the effective cell retardation value becomes half of cell retardation value in transmissive part where the LCs are homogeneously aligned. This study shows the possibility to manufacture the transflective display with a single gamma curve for reflective and transmissive region. The new device shows a high image quality with relatively easy fabrication.

• Journal of the Optical Society of Korea
• /
• v.9 no.2
• /
• pp.74-78
• /
• 2005

With the fast Q-tensor method, which can model the defect dynamics in a liquid crystal director field, the nucleation and dynamical behavior of defects is modeled. In order to model the defect, hormeotropic aligned liquid crystal cell with step inhomogeneous electrode which has a height of $1\;{\mu}m$ is used. From the simulation, we can observe the nucleation and line of the defect from surface inhomogeneity and the experiment is performed for confirmation. The experimental result is compared with numerical modeling in order to verify the simulation of the defect nucleation.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1593-1595
• /
• 2009

We demonstrate an intriguing liquid crystal display (LCD) mode that comprises an optically isotropic liquid crystal (LC) composite incorporating with inplane electric field geometry. No surface treatment, such as rubbing, is required to fabricate the LCD mode because it is based on an optically isotropic state. The measured response time was of submillisecond order. The LCD mode has several unique features such as fast response, continuous grayscale capability, and a high contrast ratio.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.251-254
• /
• 1999

A new multi-seeding process for the growth of YBa$_2$Cu$_3$Oxx single crystals was developed. This process introduces an additional heating step to peritectic temperature and a subsequent slow cooling step to the growth temperature following the point when the crystals contacted. The crystal growth was resumed thereafter. The results obtained with this new process were compared with those of the conventional growth process, in which materials were only kept at the growth temperature. It was observed that the liquid phase between crystals were almost completely eliminated, but that Y2ll grains were grown during this new process. There was no significant improvement in trapped magnetic field over the conventional process, which is believed to be due to the cracks generated during the oxygen heat treatment or to the growth of YBa$_2$Cu$_3$Ox grains.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.421-422
• /
• 2007

The fringe electric field driven transflective liquid crystal display with dual orientation has a problem that the voltage-dependent transmittance and reflectance curves do not match each other, requiring a dual driving circuit to achieve a high electro-optic performance. Optimizations of the electrode structure in the array substrate and rubbing direction solve this problem so that the transflective display with a single gap and a single gamma curve for reflective and transmissive region is possible.

• Current Optics and Photonics
• /
• v.3 no.3
• /
• pp.215-219
• /
• 2019

Chromatic aberrations induced by Risley prisms made of a single material can be substantially compensated using a liquid crystal spatial light modulator while still keeping the prism pairs compact, simple and lightweight. A ${\pm}10^{\circ}$ optical scanning imaging system with ${\pm}2^{\circ}$instantaneous field based on LC-SLM correction is designed as an example. The ultimate simulation results show that this kind of scheme is an effective way of improving imaging performance dynamically across the full field of scanning.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.11 no.5
• /
• pp.207-210
• /
• 2001

Metal-organic VPE (MOVPE) epitaxial growth procedure and related device fabrication technique are reported for GaInP-based epitaxial materials and devices. For GaInP/GaInAs two-dimensional electron-gas field-effect transistor (TEGFET), a promising epitaxial stacking structure resulting in enhanced electron mobility is given. In conjunction with this, a new device fabrication technique to improve luminous intensity of GaInP-based LED is also shown.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.10 no.2
• /
• pp.128-133
• /
• 2000

Numerical analysis of the transport phenomena in an inductively coupled plasma reactor was conducted with two-dimensional axisymmetric model including the electromagnetic field model, electron and species density models. The spatial distribution of the charged species in the ion flux to the wafer have been calculated to examine the influence of the process conditions including antenna and reactor geometry. The antenna radius had a significant influence on the plasma state and axial ion flux distribution.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.3
• /
• pp.284-290
• /
• 1995

다공성 실리콘의 기공은 n형 실리콘의 경우 기판에 수직으로 성장하여 이는 큰 곡률을 가지는 기공 끝 부분에서의높은 전기장에 의한 tunneling 기구로 설명된다. 본연구에서는 불산 수용액에서 전기화학적인 방법으로 다공성 실리콘을 제조할 때 n형 단결정 실리콘 기판과 전해질 용액의 계면에서의 전압 분포를 Poisson식에 의하여 수치적으로 계산하였다. 이 전압 분포로 기공 벽에서의 전기장 세기 및 전류 세기를 구하여 기공이 기판에 수직으로 성장하는 것을 설명하였다. 기공 사이의 거리는 고갈층의 두께에 의하여 결정되며, 고갈층의 두깨를 계산하여 그 원인에 대해서도 고찰하였다.