• Electrical & Electronic Materials
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• v.9 no.5
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• pp.498-505
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• 1996

In the present work, we have developed the simulator to optimize the process conditions of the AR(antireflection) and HR(high-reflection) coatings for the high power laser diode. The simulator can run on the PC. After making the simple optical model, we establish the Maxwell equations for the model by the operator conversion. By using the Mathematica, we derive a matrix for the multilayer system by applying the equations to the model and optimize the AR and HR coating process conditions by obtaining the reflection rate from the matrix. We also prove the validity of the simulator by comparing the simulation with the characteristics of the laser diode which is AR and HR coated according to the optimized conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.206-209
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• 2003

The purpose of AR and HR coating is acquire the very low reflection rate and the high reflection rate through the deposition of a thin film using the refraction ofmaterial. Basically if the high refractive material and the low refractive material are chosen and the condition for the experiment is determined, then we solve theproject with the optical design and multi thin film coating. First of all, we choose $SiO_2$for the low refractive material and $TiO_2$ for the high refractive material and apply Sputtering System easy to control the refraction rate and excellent in reconstruction to the equipment of thin film multiplication. For the control of the refraction rate and growth rate we modify RF Power and the ratio of Gas(Ar:O2), And we use Ellipsometer for estimation and analysis of the refraction rate and growth rate and AFM&SEM for the analysis of surface and component.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.29-34
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• 1995

Mirror coating is applied to laser facets to improve properties of edge emitting laser diodes. In this experiment, InGaAsP/GaAs high power laser diodes were studied with respect to different degrees of anti-reflective coating. Sputterred $Al_{2}$O$_{3}$ was used as the coating material and the HR coating was kept constant at 90%. Threshold current density, differential quantum efficiency, emission wavelength and the operating current at 500mW were measured for a range of AR coating and compared with theoretically calculated values; that showed good agreements. Precise wavelength control is important for laser diodes for solid state pumping because of small absorption bandwidth. In addition, since these lasers operate under CW condition, a lowest possible operating current for a given power is desired in order to minimize the heat produced. From the results of this experiment, we were able to obtain a optimum range of AR coatings for minimum operating current. The wavelength can be varied up to 4nm within this range.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.395-402
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• 1997

We have obtained the optimum thickness of anti-reflection(AR) coating on one of facets of a $\1.55mu\textrm{m}$ InGaAsP MQW FP semiconductor laser by in-site monitoring of the light emitted from the rear facet during the film deposition on the fore facet. The optimum thickness of $SiO_x$ thin film whose refractive index is 1.85 was found to be 188 nm. The reflectivity of the coated facet was calculated by the threshold current ratio of before and after AR coating, which was obtained from exprimental data, and it was about 2$\times$ $10^{-4}$. The results show that the output power is increased by 87% at bias current 60 mA, the slope efficiency is increased by 3.4 times, and the threshold current is increased by 2.64 times. By in-situ depositing of the $Si/SiO_2$ thin film HR coating on the rear facet, the output power was increased by 160% than before the AR and HR coatings, the slope efficiency was increased by 3.8 times, the threshold current was increased by 1.07 times, which is similar to the value of before AR coating. Due to the AR and HR coatings the output light power characteristics were enhanced.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.103-106
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• 2006

Semiconductor laser diode has a reflective facet in a both-ends side fundamentally. Laser performance for improving, Anti-Reflection and High-reflection coating on the facet of semiconductor laser diode. To prevent internal feedback from both facets for realizing superluminescent diode and reducing the reflection-induced intensity noise of laser diode, it's key techniques are AR/HR coatings. In the study AR coating film were manufactured by Ion-Assisted Deposition(IAD) system. Then manufactured coating film measurement electrical properties(L-I-V, Se, Resistor) and Optical properties (wavelength FFP)

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.908-913
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• 1997

Multilayer NbCxC1-x/Y2O3/Ti were sputter-coated on the alumina substrate, starting with a 0.7 ㎛ thick NbCxC1-x layer grown on substrate, followed by 0.7 ㎛ thick Y2O3 layer and 1 ㎛ thick Ti layer. To find out the optimum conditions for thickness uniformity and adhesion, sputtering works have been done with the variation of sputtering power and Ar pressure. After vacuum annealing at 950℃ and 1000℃, the thermal stability of the NbCxC1-x/Y2O3/Ti coated alumina substrates has been investigated by peel off test. The coating scheme didn't cause any debonded layer after an annealing at 950℃ for 3hrs. However, it was peeled off after annealing at 1000℃ for 3hr. It was found that the thermal stability of Al2O3/NbCxC1-x/Y2O3/Ti coating scheme changed with the NbCxC1-x composition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.417-418
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• 2008

Transparent conductive oxide (TCO) are necessary as front electrode or anti-reflecting coating for increasing efficiency of LED and Photodiode. In this paper, aluminum-doped Zinc oxide films(AZO) were prepared by DC magnetron sputtering on glass(corning 1737) and Si substrate at temperature of $100^{\circ}C$ and then annealed at temperature of $400^{\circ}C$ for 1hr in Ar and vaccum. The AZO films were etched in diluted HCL (0.5 %) to examine the surface morphology properties. After annealing, Structural and electrical property were investigated. The c-axis orientation along (002) plane was enhanced and the electrical resistivity of the AZO film decreased from $1.1\times10^{-1}$ to $1.6\times10^{-2}{\Omega}cm$. We observed textured structure of AZO thin film etched for 2s.

• Journal of the Korean institute of surface engineering
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• v.34 no.2
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• pp.105-114
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• 2001

$Al_2$$O_3$ coatings were deposited on M2 high speed steels by the plasma enhanced chemical vapor deposition (PECVD) process, using a gas mixture of AlC1$_3$, $H_2$, $CO_2$ and Ar $Al_2$$O_3$ coatings had interference color and showed amorphous phase. $A1_2$X$A1_3$/($Ti_{0.5}$ /$Al_{0.5}$ )N double layer coatings were produced in the sequence of substrate $NH_3$ plasma pretreatment, ($Ti_{0.5}$$Al_{0.5}$)N depoition process, $Al_2$$O_3$ deposition process. $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings showed NaCl structure in ( $Ti_{0.5}$A $l_{0.5}$)N layer and amorphous phase in A1$_2$ $O_3$ layer. It was shown that $Al_2$ $O_3$ columns continuously grew onto ( $Ti_{0.5}$A $l_{0.5}$)N columns. ( $Ti_{0.5}$A $l_{0.5}$)N single coating and $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coating were oxidized at $700^{\circ}C$, 80$0^{\circ}C$, 90$0^{\circ}C$ for 1hr, 3hr in atmosphere. At 80$0^{\circ}C$, single layer coatings were oxidized, which were examined substrate oxide particle. But $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings maintained the asdeposited state. Therefore, $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings have moreexcellent oxidation resistance than ( $Ti_{0.5}$A $l_{0.5}$)N single layer coatings.X> 0.5/)N single layer coatings.s.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.167-172
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• 2013

Titanium dioxides nanoparticles coated aluminum oxide powders were fabricated by pulsed laser deposition (PLD) with Nd : YAG laser at 266 nm. The Pulse laser energy is 100 mJ/pulse. During the irradiation of the focused laser on the $TiO_2$ target, Ar gas is supplied into the chamber. The gas pressure is varied in a range of $1{\times}10^{-2}$ to 100 Pa. Titanium dioxides nanoparticles deposited aluminum oxide powders were characterized by using energy dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscopy (HR-TEM), in order to understand the effect of Ar background gas on surface morphology and properties of the powders. The coated $TiO_2$ nanoparticles had nanosized spherical shape and the crystallite sizes of 10~30 nm. The morphology of coated $TiO_2$ nanoparticles is not affected by gas pressure. However, the particle size and crystallinity slightly increased with the increase of gas pressure. According to this technique, the size and crystallinity of nanoparticles can be easily controlled by controlling pressure during the laser irradiation.

• Journal of the Korean Electrochemical Society
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• v.7 no.2
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• pp.94-99
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• 2004

Anode-supported flat tubular solid oxide fuel cell (SOFC) was investigated to increase the cell power density. The anode-supported flat tube was fabricated by extrusion process. The porosity and pore size of Ni/YSZ ($8mol\%$ yttria-stabilized zirconia) cermet anode were $50.6\%\;and\;0.23{\mu}m$, respectively. The Ni particles in the anode were distributed uniformly and connected well to each other particles in the cermet anode. YSZ electrolyte layer and multilayered cathode composed of $LSM(La_{0.85}Sr_{0.15})_{0.9}MnO_3)/YSZ$ composite, LSM, and $LSCF(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.7}O_3)$ were coated onto the anode substrate by slurry dip coating, subsequently. The anode-supported flat tubular cell showed a performance of $300mW/cm^2 (0.6V,\; 500 mA/cm^2)\;at\;500^{\circ}C$. The electrochemical characteristics of the flat tubular cell were examined by ac impedance method and the humidified fuel enhanced the cell performance. Areal specific resistance of the LSM-coated SUS430 by slurry dipping process as metallic interconnect was $148m{\Omega}cm^2\;at\;750^{\circ}C$ and then decreased to $148m{\Omega}cm^2$ after 450hr. On the other hand, the LSM-coated Fecralloy by slurry dipping process showed a high area specific resistance.