• 한국재료학회지
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• 제8권5호
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• pp.419-423
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• 1998

매립형 InGaAnP/InP 레이저 다이오드 제작을 위한 질량 이동 현상의 최적화에 대한 연구를 수행하였다. Double heterostructure 레이저 다이오드 구조의 1차 성장은 액상 에피 성장 장치를 이용하였으며, 메사 에칭하였다. 활성층을 [110] 방향으로 선택적으로 에칭 한 후, 액상 에피 성장 장치를 이용하여 질량 이동 현상을 발생시켜 매립형 구조를 형성시켰다. 질량 이동 현상의 임계온도는 40분간 유지시켰을 때 $670^{\circ}C$로 나타났으며 재현성 있게 질량 이동 현상이 발생하였다. 질량 이동 현상에 의해 성장된 층의 폭은 온도증가에 따라 약간 증가하였다.

• Journal of Oral Medicine and Pain
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• 제19권1호
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• pp.33-43
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• 1994

The purpose of this paper was to observe the influence of Ga-As semiconductor-low power generating laser on she appearance and actions of tenascin, extracellular matrix, as healing process of intentional wound on the experimental animals is taking place. 35 rabbits were divided into control and experimental group. ; and on each, 3mm-long and 2mm-deep, surgical wounds were created on buccal oral mucosa and thoracodorsal portion of skin. Ga-As laser was applied to the experimental group starting a day of the day the wounds were created , the laser was applied for 5 minutes every other day. Tissue samples were taken after the 2, 4, 7, 10, and 14 days after wound formation. Then tile healing process of experimental and control groups were observed and compared, using light microscope. Afterwards, the samples were immunohistochemical stained and again observed tenascin by quantitative measuring. The following results were obtained : 1. Tenascin was observed prevalently on epithelial cells, border area of dermis, and interstitial matrix between connective tissue layers in both experimental and control groups. 2. In oral mucosa, the experimental group showed significant increase in the appearance of tenascin after 4 days compared to the control group, but after 10 days, it decreased to a point which is even less than the control group. 3. In the skin samples, the pattern of appearance of tenascin was the same in both groups, but there was some difference concerning when the peak period was shown, In the experimental group, the peak period of tenascin expression was the 7 days after wound formation in epithelium and connective tissue. In the control group, the peak period was 10 days after. 4. In both the experimental and control groups, tenascin first appeared in the epithelium near the wound area and submucosa, and then spread on the underlying connective tissue. In conclusion, appearance of tenascin is closely related to regeneration of epithelium and development of granulation tissue : therefore, low power laser, which fastnes appearance of tenascin, is sure to faciltate healing process of oral mucosa.

• Journal of the Optical Society of Korea
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• 제11권3호
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• pp.138-141
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• 2007

We suggest that supercontinuum can be used for absorption spectroscopy to observe the exciton levels of a semiconductor nano-structure. Exciton absorption spectrum of a GaAs/AlGaAs quantum well was observed using supercontinuum generated by a microstructrured fiber pumped by a femtosecond (fs) pulsed laser. Significantly narrower peaks were observed in the absorption spectrum from 11 K up to room temperature than photoluminescence (PL) spectrum peaks. Because supercontinuum is coherent light and can readily provide high enough intensity, this method can provide a coherent ultra-broad band light source to identify exciton levels in semiconductors, and be applicable to coherent nonlinear spectroscopy such as electromagnetically induced transparency (EIT), lasing without inversion (LWI) and coherent photon control in semiconductor quantum structures.

• 한국표면공학회지
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• 제23권4호
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• pp.197-207
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• 1990

Atomic layer epitaxy is a relatively new epitaxial pprocess chracterized by the alternate and separate exposure of a susbstrate surface to the reactants contaning the constituent element of a compound semicoductror. The ideal ALE is expected to provide sevral advantageous as petcts for growing complicated heterostrutures such as relativly easy controls of the layer thinkness down to a monolayer and in forming abrupt heterointerfaces though monolayer self-saturatio of the growth. In addition, since ALE is stongly dependent on the surface reaction, the growth can also be controlled by photo-excitation which provides activation can be energies for each step of the reaction paths. The local growth acceleration by photo-excitation can be exploited for growing several device strures on the same wafer, which provides another important practical advantage. The ALE growth of GaAs has advanced to the point the laser opertion has been achieved from AlGs/GaAs quantun well structures where thee active layers were grown by thermal and Ar-laser assisted ALE. The status of the ALE growth of GaAs and other III-V compounds will be reviewed with respect to the growth saturation behavior and the electrical properties of the grown crystals.

• 전자공학회논문지D
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• 제34D권3호
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• pp.52-59
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• 1997

Design and performance of principal four ICs for the 10-Gb/s optical communication system are presented. AlGaAs/GaAs HBTs are basic devices to implement a laser diode driver, apre-amplifier, and a limiting amplifier, and GaInP/GaAs HBTs are used for an AGC amplifier. We fbricated 11.5-GHz LD driver, a pre-amplifier, and a limiting amplifier, an dGaInP/GaAs HBTs are used for an AGC amplifier. We fabricated LD deriver, 10.5 GHz pre amplifier, 7.2 GHz AGC amplifier, and 10.3 GHz limiting amplifier, optimized circuit design and the stabilized MMIC fabrication process.

• 한국광학회지
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• 제14권3호
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• pp.327-330
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• 2003

본 논문에서는 도파로층이 1.3 $\mu\textrm{m}$ InGaAsP긴 파장 가변 BT(butt-coupled)-DBR(distributed bragg reflector)-LD(laser diode)를 제작하고, 특성을 측정하였다. Butt 결합 성장면의 성장조건을 건식식각과 선택식각 방법과 MOCVD(metal organic chemical vapor deposition)성장으로 최적화 한 후 활성층과 도파로층의 결합 효율을 측정한 결과 결합 효율이 85% 이상으로 나타났으며, 제작된 BT-DBR-LD에 연속전류를 인가 했을 때, 평균 임계전류는 약 21 ㎃, 최대 광출력이 25 ㎽ 이상으로 나타났다. 또한 위상제어 영역과 DBR영역에 각각 25㎃와 50 ㎃의 전류를 주입하여도 급격한 광출력 변화와 포화현상이 나타나지 않았다 이때 최대 파장 가변 폭은 7.4 nm, SMSR비는 40 ㏈이상으로 나타났다.

• 전자공학회논문지D
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• 제34D권11호
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• pp.20-24
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• 1997

We have successfully fabricated high power (~20W) laser diode array, which are useful for pumping Nd:YAG lasers. The laser diode aray has 20 100.mu.m-wide cahnnels of which space was adjusted to 350.mu.m to improve thermal characteristics. And channel width is 100.mu.m. For an uncoated LD array, the output power of 15.66W has been obtained at 41A under quasi-CW operation, which results in about 0.42W/A slope efficiency. After aR(5%) and HR (95%) coatings on both facets, the output power was improved up to 21.18W at 40A under the same operation as above and the slope efficiency was 0.795W/A. On the other hand, by using a near field measurement system consisting of objective lens, eyepiece, CCD camera and image processing board, the typical near field patten of 1*20 LD array was observed.

• 한국융합학회논문지
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• 제8권5호
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• pp.161-167
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• 2017

상온에서 단일소자의 경우 $0.98{\mu}A$ 문턱전류를 나타내는 $32{\times}32$ 광양자테 레이저 어레이를 제작하였다. 제작된 어레이의 전체 소자들의 문턱전류 및 밀도, 전압은 20 mA, $0.068A/cm^2$, 1.38 V의 값을 나타내었다. 발광 광양자테 어레이는 GaAs 물질이 다중-양자 우물 활성 영역을 구성하고, 칩이 차지하는 면적은 $1.65{\times}1.65mm^2$였으며, 소자들의 피크파워 파장은 $858.8{\pm}0.35nm$, 상대적인 레이저 세기는 $0.3{\pm}0.2$, 선폭은 $0.2{\pm}0.07nm$로 비교적 균일한 특성을 보였다. 또한, 레이저 어레이의 각도 의존적 청색 이동 특성을 이용한 파장 분할 멀티플렉싱 시스템 실험을 진행하였고, 각도에 따라 10 nm 정도 파장이 변하는 현상을 발견하였으며, 거리에 따른 레이저 세기를 측정한 결과 6 m에서도 감지할 수 있음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.110-111
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• 2007

In order to form a p-type ZnO thin film, ZnO thin film is deposited by pulsed laser deposition(PLD) on GaAs substrate followed by nermal treatment that ensures the diffusion of As atoms from the GaAs substrate to the ZnO thin films. Photoluminescence (PL) measurement reveals that the improved qualify of ZnO thin films is acquired at the growth temperature of $400^{\circ}C$. It is ZnO film grown at $100^{\circ}C$ that shows the change from n-type to p-type by the thermal treatment. Measured carrier concentration in the film is changed from $-5.70{\times}10^{13}\;to\;9.09{\times}10^{18}$.

• The Journal of Korean Physical Therapy
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• 제14권4호
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• pp.87-94
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• 2002

Low intensity laser irradiation is potential physical agent that triggers the muscle regeneration by previous study. In muscle regeneration, a number of growth factors also promotes that is triggered in response to muscle damage. The transforming growth factor(TGF)-$\beta$ is involved in the activation of cell proliferation and the inhibition of cell differentiation in muscle regeneration. This is secreted not only autocrine system but also paracrine and endocrine. Therefore, We investigated that effects of Gallium aluminum arsenide(GaAlAs) diode laser for the expression of TGF-$\beta$ on lumbar spinal cord after extensor digitorum muscle crush injury. After laser irradiation, the immunoreactivity of TGF-$\beta$ was increased bilaterally in gray mater of spinal cord. Especially, in 1 day, experimental group was highed than control, and in 3 day, lateral motor nucleus were storong immunoreactivy of TGF-$\beta$. Also, in 1 and 2 day, TGF-$\beta$ was showed in white mater as well as gray mater, but in 3 day, only showed in gray mater. These data may suggests to the establishment of laser irradiation on spinal cord for skeletal muscle injury.