• Current Optics and Photonics
• /
• v.5 no.1
• /
• pp.77-77
• /
• 2021

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1604-1607
• /
• 2009

YAG laser crystallization of Si-based thin film deposited on plastic substrate has been studied. The Si-based thin films as crystallization precursor are with varied hydrogen (H) content. The effect of the H content on the crystallinity of the resulted poly-Si film has been investigated. The experimental results of the poly-Si crystallized by doublefrequency YAG laser shows that the initial dehydrogenation process could be left out if ${\mu}c$-Si was adopted as the crystallization precursor. The YAG laser annealing condition on plastic substrate and the crystallization results have been discussed in the paper.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.430-430
• /
• 2012

The surface recombination velocity of the silicon solar cell could be reduced by passivation with insulating layers such as $SiO_2$, SiNx, $Al_2O_3$, a-Si. Especially, the aluminium oxide has advantages over other materials at rear surface, because negative fixed charge via Al vacancy has an additional back surface field effect (BSF). It can increase the lifetime of the hole carrier in p-type silicon. The aluminium oxide thin film layer is usually deposited by atomic layer deposition (ALD) technique, which is expensive and has low deposition rate. In this study, ICP-assisted reactive magnetron sputtering technique was adopted to overcome drawbacks of ALD technique. In addition, it has been known that by annealing aluminium oxide layer in nitrogen atmosphere, the negative fixed charge effect could be further improved. By using ICP-assisted reactive magnetron sputtering technique, oxygen to nitrogen ratio could be precisely controlled. Fabricated aluminium oxy-nitride (AlON) layer on silicon wafers were analyzed by x-ray photoelectron spectroscopy (XPS) to investigate the atomic concentration ratio and chemical states. The electrical properties of Al/($Al_2O_3$ or $SiO_2/Al_2O_3$)/Si (MIS) devices were characterized by the C-V measurement technique using HP 4284A. The detailed characteristics of the AlON passivation layer will be shown and discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.04a
• /
• pp.78-80
• /
• 2006

The hybrid thin-film (HTF) passivation layer composed of the Ultra Violet (UV) curable acrylate layer and MS-31 (MgO:$SiO_2$=3:1wt%) layer was adopted in organic light emitting device (OLEO) to protect organic light emitting materials from penetrations of oxygen and water vapors. The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007gm/m^{2+}day$ at $37.8^{\circ}C$ and 100% RH. This value was within the limited range of the sensitivity of WVTR measurements. And the lifetime of the HTF passivated device became almost three times longer than that of the bare device. The HTF on the OLEO was found to be very effective in protect what from the penetrations of oxygen and moisture.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.961-965
• /
• 2006

White organic LED spectrum for lighting and displaying should be designed for high luminous efficiency as well as good chromaticity coordinate, pleasant correlated color temperature and color rendering. A program based on Matlab was made to make these calculations convenient. The chromaticity coordinate and luminous efficiency was calculated according to the CIE 1931 colorimetric system, while the correlated color temperature(CCT) was calculated based on CIE 1960 UCS diagram. The color rendering characteristics were evaluated according to the CIE Color Rendering Index (CRI), using Ra, Ri and ${\bigtriangleup}E$ from the 14 color samples defined in CIE13.3.

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.02a
• /
• pp.315-316
• /
• 2008

• The Journal of the Korea institute of electronic communication sciences
• /
• v.3 no.3
• /
• pp.158-164
• /
• 2008

This project investigates an optimum phase design implementing a 256 phase Opto-ULSI processor for multi-function capable optical networks. The design of an 8 phase processor is already in construction and will provide the initial base for experimentation and characterization. The challenge is to be able to compensate for the non-linearity of the liquid crystal, find an optimum phase, and implement a larger scale Opto-ULSI processor. This research is oriented around the initial development of an 8 phase Opto-ULSI processor that implements a Beam Steering(BS) Opto-ULSI processor(OUP) for integrated intelligent photonic system(IIPS), while investigating the optimal phase characteristics and developing compensation for the non-linearity of liquid crystal.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.324-325
• /
• 2014

Quantum wells infrared photodetectors (QWIPs) have been used to detect infrared radiations through the principle based on the localized stated in quantum wells (QWs) [1]. The mature III-V compound semiconductor technology used to fabricate these devices results in much lower costs, larger array sizes, higher pixel operability, and better uniformity than those achievable with competing technologies such as HgCdTe. Especially, GaAs/AlGaAs QWIPs have been extensively used for large focal plane arrays (FPAs) of infrared imaging system. However, the research efforts for increasing sensitivity and operating temperature of the QWIPs still have pursued. The modification of heterostructures [2] and the various fabrications for preventing polarization selection rule [3] were suggested. In order to enhance optical performances of the QWIPs, double barrier quantum well (DBQW) structures will be introduced as the absorption layers for the suggested QWIPs. The DBWQ structure is an adequate solution for photodetectors working in the mid-wavelength infrared (MWIR) region and broadens the responsivity spectrum [4]. In this study, InGaAs/GaAs/AlGaAs double barrier quantum well infrared photodetectors (DB-QWIPs) are successfully fabricated and characterized. The heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIPs are grown by molecular beam epitaxy (MBE) system. Photoluminescence (PL) spectroscopy is used to examine the heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIP. The mesa-type DB-QWIPs (Area : $2mm{\times}2mm$) are fabricated by conventional optical lithography and wet etching process and Ni/Ge/Au ohmic contacts were evaporated onto the top and bottom layers. The dark current are measured at different temperatures and the temperature and applied bias dependence of the intersubband photocurrents are studied by using Fourier transform infrared spectrometer (FTIR) system equipped with cryostat. The photovoltaic behavior of the DB-QWIPs can be observed up to 120 K due to the generated built-in electric field caused from the asymmetric heterostructures of the DB-QWIPs. The fabricated DB-QWIPs exhibit spectral photoresponses at wavelengths range from 3 to $7{\mu}m$. Grating structure formed on the window surface of the DB-QWIP will induce the enhancement of optical responses.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1306-1309
• /
• 2005

Highly efficient and bright organic light-emitting diodes (OLEDs) have been realized using the thin alkali compound films (TACFs) at the interface between an emitting layer and an electron transporting layer with conventional organic layers. By comparing the performance of the device as a function of position with the TACFs, we propose the optimal position of the TACFs in the tris-(8-hydroxyquinoline) aluminum (Alq3). A device with the ACFs showed high luminance of over 12 500 cd/m2, luminance efficiency of more than 12 cd/A, and power efficiency of more 4.5 lm/W, respectively.

• Membrane and Water Treatment
• /
• v.8 no.1
• /
• pp.35-50
• /
• 2017

The theoretical membrane gas absorption module treatments in a hollow fiber gas-liquid membrane contactor using Happel's free surface model were obtained under countercurrent-flow operations. The analytical solutions were obtained using the separated variable method with an orthogonal expansion technique extended in power series. The $CO_2$ concentration in the liquid absorbent, total absorption rate and absorption efficiency were calculated theoretically and experimentally with the liquid absorbent flow rate, gas feed flow rate and initial $CO_2$ concentration in the gas feed as parameters. The improvements in device performance under countercurrent-flow operations to increase the absorption efficiency in a carbon dioxide and nitrogen gas feed mixture using a pure water liquid absorbent were achieved and compared with those in the concurrent-flow operation. Both good qualitative and quantitative agreements were achieved between the experimental results and theoretical predictions for countercurrent flow in a hollow fiber gas-liquid membrane contactor with accuracy of $6.62{\times}10^{-2}{\leq}E{\leq}8.98{\times}10^{-2}$.