• 한국진공학회지
• /
• 제20권5호
• /
• pp.345-355
• /
• 2011

GaAs나 InP 기반의 high electron mobility transistor (HEMT) 소자들은 우수한 마이크로파 및 밀리미터파 주파수 특성 및 이에 따른 우수한 저잡음 특성을 가지고 있다. GaAs 기판 위에 점진적으로 성장된 메타몰픽(Metamorphic) HEMTs (MHEMTs)는 InP 기판 위에 성정한 HEMT에 비해 비용 측면에서 커다란 장점을 가지고 있다. 본 논문에서는 이러한 MHEMT의 DC/RF 소신호 특성을 예측하기 위하여 InAlAs/InGaAs/GaAs MHEMT 소자들의 DC/RF 소신호 주파수 특성을 시뮬레이션하였다. 2차원 소자 시뮬레이터의 hydrodynamic 전송 모델을 사용하여 $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ 이종접합 구조를 갖는 제작된 0.1-${\mu}m$ ${\Gamma}$-게이트 MHEMT 소자에 대하여 파라미터 보정 작업을 수행한 후, MHEMT 소자들에 대해 DC 특성 및 RF 소신호 주파수 특성을 시뮬레이션하고 실험 데이터와 비교 분석하였다. 또한, 게이트 리세스 구조에 따른 MHEMT 소자들의 DC/RF 특성을 시뮬레이션하고 비교 분석하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 추계학술대회 논문집
• /
• pp.10-12
• /
• 1996

AlGaAs/GaAs Heterojunotion Bipolar Transistors (HBTs) with various emitter areas were fabricated and the device size dependence on the current gain was examined. With the different emitter areas, the passivated devices having the same peripheral length were fabricated and measured. The measured base current density in the Gummel plots shows an ideality factor of nearly 2. It is found that as the emitter area becomes small, the base current density with the ideality factor of 2 increases linearly, and as the emitter perimeter/area ratio becomes large, the surface recombination current density component increases. The current gain performance in AlGaAs/GaAs HBTs is mainly determined by either the larger emitter area or the smaller ratio of the emitter perimeter to the emitter area. These results will be compared with experimental works for GaInP/GaAs HBTs

• 한국광학회:학술대회논문집
• /
• 한국광학회 2009년도 동계학술발표회 논문집
• /
• pp.525-526
• /
• 2009

we investigated the effect of rapid thermal annealing (RTA) temperature on photoluminescence (PL) of 635 nm InGaP/InGaAlP multiple quantum well structure. RTA is performed with the quantum well structure with 5.5 nm of well width. The highest PL peak intensity is shown at 1 min. of RTA at $720^{\circ}C$ sample as 3 times higher as compared to the as-grown sample. The effect may be assigned to an expected reduction in number of nonradiative recombination centers in the quantum well.

• 공업화학
• /
• 제30권4호
• /
• pp.504-508
• /
• 2019

GaInP/AlGaInP 이종접합 구조를 제안하고 집광 조건에서 가장 높은 효율을 달성한 III-V 화합물 반도체 다중접합 태양전지의 맨 위 subcell에 주로 사용되는 GaInP 동종접합 구조를 대체해 이종접합 구조가 응용될 가능성에 대하여 조사하였다. $2^{\circ}$ off 된 웨이퍼와 $10^{\circ}$ off 된 서로 다른 off-cut 방향을 갖는 두 종류의 GaAs 기판 위에 성장된 태양전지의 특성을 집광 조건에서 측정하고 비교하였다. $10^{\circ}$ off 된 태양전지에서 더 높은 단락전류와 변환효율을 얻었다. 1 sun 조건에서 $10^{\circ}$ off 된 기판 위에 제작된 $2{\times}2mm^2$ 면적의 태양전지에서 $9.21mA/cm^2$의 단락전류밀도와 1.38 V의 개방 전압이 측정되었다. $10^{\circ}$ off 기판 위에 제작된 $5{\times}5mm^2$ 태양전지에서 집광도 증가에 따라 곡선인자(fiill factor)가 감소하여 변환효율은 6.03% (1 sun)에서 5.28% (20 sun)로 측정되었다.

• The Journal of Korean Physical Therapy
• /
• 제14권2호
• /
• pp.234-249
• /
• 2002

This study was performed, using c-fos and Substance P, to investigate the effect of GaAlAs laser on acute pain model induced by wound in lumbar region's spinal level. The test group was divided into control and experimental group. Control group is shamed group(c-fos and substance P expression after non-irradiation by a GaAlAs laser), The experimental group was divided into two subgroups: one is experimental group I (c-fos expression after irradiation by a GaAlAs laser), and the other is experimental group II (substance P expression after irradiation by a GaAlAs laser). The results of this study were as following: 1. The numbers of c-fos immunoreactive neuron in spinal cord was increased markedly 1 day after wound, and decreased gradually from 1 day to 2 days in wound with GaAlAs laser irradiation. 2. The changes of the average percentages of substance P immunoreactive neurons in spinal cord was increased markedly 1 day after wound, and decreased gradually from 1 day to 2 days in wound with GaAlAs laser irradiation. Therefore, decreasing the changes of c-fos and substance P expression after irradiation by a GaAlAs laser indicates and GaAlAs laser have effect on pain control.

• 한국결정성장학회지
• /
• 제11권5호
• /
• 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.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.441-441
• /
• 2012

Franz Keldysh Oscillation (FKO)은 p-n 접합 구조의 Photoreflectance (PR) spectra에서 표면 및 계면의 전기장(electric field) 특성을 반영한다. InAs/GaAs 양자점 태양전지(Quantum Dot Solar Cell, QDSC) 구조에서 InAs 양자점 층 전후에 AlGaAs 층을 삽입하여 퍼텐셜 장벽(potential barrier) 두께에 따른 PR spectra 및 GaAs-matrix에서 FKO 주파수 특성을 비교 분석하였다. InAs/GaAs 양자점 태양전지는 p-i-n 구조의 i-GaAs에 2.0 monolayer (ML), 8주기의 InAs 양자점 층을 삽입하여 Molecular Beam Epitaxy (MBE) 방법으로 성장하였다. 각 양자점 층 전후에 두께가 각각 0.0, 1.6, 2.8, 6.0 nm인 AlGaAs 층을 삽입하여 퍼텐셜 장벽 두께에 따른 FKO 주파수 변화를 관측하였다. 또한 태양전지 구조의 전기장 분포를 좀 더 용이하게 관측하기 위해 여기 광의 세기(power intensity)를 충분히 낮추어 Photovoltaic effect에 의한 내부 전기장의 변화를 최소화하여 비교 분석하였다. InAs/GaAs 양자점 태양전지 구조에서 AlGaAs 장벽층이 없는 경우, PR spectra의 Fast Fourier Transform 결과에 반영되는 FKO 주파수 특성은 p-i-n 구조 계면에서 공핍층(depletion region)의 space charge field보다 양자점 층의 내부 전기장에 의한 FKO 주파수가 더 큰 진폭(amplitude)을 보였다. 반면에, AlGaAs 장벽층이 삽입되면 두께가 커짐에 따라 p-i-n 구조 계면의 space charge field에 의해 더 큰 진폭의 FKO 주파수가 관측되었다. 이는 AlGaAs 장벽층이 삽입됨으로써 양자점 층 내 양자 상태 수 및 여기광에 의한 캐리어의 수와 관련이 있음을 확인하였으며, 결과적으로 GaAs-matrix에서 p-i-n 구조 계면의 space charge field에 영향을 미치게 됨을 알 수 있다. 이러한 PR 특성 결과들을 InAs/GaAs 양자점 태양전지의 설계 및 제조에 반영함으로써 양자효율 증대에 기여할 것으로 기대된다.

• 한국항해학회지
• /
• 제15권3호
• /
• pp.99-106
• /
• 1991

In order to grow InGaAsP epitaxial layer on GaAs by LPE, an accurate phase diagram for In-Ga-As-P quarternary compounds is required. But the short wavelength InGaAsP/GaAs phase diagram for full wavelength range was not yet reported. In this study, therefore, a theoretical calculation has been carried out by using thermodynamic's equation for InGaAsP/GaAs in order to get the relation between the mole fraction of the sloute and solid phase compounds. And the calculation being compared with the dta of Kawanishi et. al, the result has been shown that his phase diagram obtained by the calculation can apply to growing InGaAsP/GaAs by LPE.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.118-119
• /
• 2013

High power, short wavelength red laser diodes (LDs) have attracted significant interests in a variety of fields due to their advantages in terms of reliability, compactness and cost. The higher brightness for human eyes is required, the shorter wavelength like 630 nm is necessary with higher output power. In this respect, LDs are promising as alternative candidates of gas or dye lasers for such applications due to their small size, high optical/electrical power conversion efficiency, robustness and so on. The crystalline quality of GaInP-AlGaInP multiple quantum wells (MQWs) and AlInP cladding layers is a crucial part in the device performance of GaInP red LDs. Here, we first investigated the effect of Si diffusion on the optical properties of GaInP-AlGaInP MQWs grown with different growth temperatures. Secondary ion mass spectroscopy (SIMS) measurements revealed that both the Mg and Si diffusion into MQW active region was significant. To reduce such diffusion, we employed undoped Mg and Si diffusion barrier and could improve the properties.Without both Mg and Si diffusion barriers, no lasing emission was observed. However, lasing emission was observed clearly for the red LDs with both Mg and Si diffusion barriers. We then investigated the temperature dependent optical properties of MQW layers grown with different well thicknesses (6, 8 and 10 nm). When the well thickness was 10 nm, the better crystalline quality was obtained. However, the observed LD performances were similar, probably due to the defects and impurities in the AlGaInP layer. Further investigation with the detailed analyses will be presented later.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.295-298
• /
• 1999

AlGaAs/InGaAs power P-HEMTS (Pseudo-morphic High Electron Mobility Transistors) with 1.0-${\mu}{\textrm}{m}$ gate length for PCS applications have been fabricated. We adopted single heterojunction P-HEMT structure with two Si-delta doped layer to obtain higher current density. It exhibits a maximum current density of 512㎃/mm, an extrinsic transconductance of 259mS/mm, and a gate to drain breakdown voltage of 12.0V, respectively. The device exhibits a power density of 657㎽/mm, a maximum power added efficiency of 42.1%, a linear power gain of 9.85㏈ respectively at a drain bias of 6.0V, gate bias of 0.6V and an operation frequency of 1.765㎓.