• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.414-414
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• 2013

InGaAlAs/InP은 $1.3{\sim}1.55{\mu}m$ 레이저 다이오드 응용을 위한 InGaAsP/InP를 대체하기 위한 물질로 많은 관심을 받아왔다. 디지털 합금 InGaAlAs 다중양자우물(multiple quantum wells: MQWs) 시료는 MBE (molecular beam epitaxy) 장비를 이용하여 n-InP 기판 위에 성장하였다. 양자우물과 장벽은 각각 (InGaAs)0.8(InAlAs)0.2와 (InGaAs)0.4(InAlAs)0.6 SPSs (short-period superlattices)로 $510^{\circ}C$에서 성장하였다. 발광특성을 향상시키기 위하여 질소분위기에서 $700^{\circ}C$ $750^{\circ}C$ 또는 $800^{\circ}C$에서 30초간 열처리(rapid thermal annealing: RTA)하였다. RTA 온도에 따른 디지털 합금 InGaAlAs MQWs의 발광특성을 분석하기 위해 PL (photoluminescence)과 TRPL(time-resolved PL)을 이용하였다. RTA 온도에 따른 InGaAlAs MQWs 시료의 발광 메카니즘 및 운반자 동력학을 연구하기 위하여 발광파장 및 온도에 따른 TRPL을 측정하였다. 저온(10 K)에서 PL 피크는 RTA 온도를 $700^{\circ}C$에서 $750^{\circ}C$로 증가하였을 때 1,242 nm에서 1,245 nm로 장파장 영역으로 이동하였다가 $800^{\circ}C$에서 열처리하였을 때 단파장 영역으로 이동하여 1,239 nm에서 나타났다. 또한 PL 세기는 RTA 온도를 증가함에 따라 증가함을 보이다가 RTA 온도를 $800^{\circ}C$로 증가하였을 때 PL 세기는 감소하였다. 발광소자 개발을 위한 InAlGaAs MQWs 시료의 최적의 열처리 조건을 이러한 PL과 TRPL 결과로부터 결정할 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.316-318
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• 2003

양자우물 구조를 사용한 HEMT(High Electron Mobility Transistor)는 고속 스위칭 소자와 초고주파 통신용 소자 및 센서에에 우수한 동작특성을 갖고 있다. 본 논문에서는 AlInAs/InP HEMT의 heterostructure를 파동방정식과 Poisson 방정식을 self-consistent 한 방법으로 해석하였다. 파동방정식으로 junction의 전자농도를 계산하고, Poisson 방정식을 해석하여 potential profile에 의한 전자 농도가 heterostructure에서 self-consistent가 되도록 연산하였다. 끝으로 AlInAs/InP 구조에서 positively ionized donor, valance band에서의 hole, conduction band의 free electron과 구조내의 2DEG를 AlGaAs/GaAs 및 AlGaAs/InGaAs/GaAs와 비교하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.525-526
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• 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.

• Journal of Magnetics
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• v.20 no.4
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• pp.331-335
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• 2015

The ferromagnetic and electronic structure for the $Al_xGa_{1-x}P$ and Mn-doped $AlGaP_2$ was studied by using the self-consistent full-potential linear muffin-tin orbital method. The lattice parameters of un-doped $Al_xGa_{1-x}P$ (x = 0.25, 0.5, and 0.75) were optimized. The band-structure and the density of states of Mn-doped $AlGaP_2$ with or without the vacancy were investigated in detail. The P-3p states at the Fermi level dominate rather than the other states. Thus a strong interaction between the Mn-3d and P-3p states is formed. The ferromagnetic ordering of dopant Mn with high magnetic moment is induced due to the (Mn-3d)-(P-3p)-(Mn-3d) hybridization, which is attributed by the partially filled P-3p bands. The holes are mediated with keeping their 3d-characters, therefore the ferromagnetic state is stabilized by this double-exchange mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.158-158
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• 2009

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.431-435
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• 2009

The apparatus has been fabricated using the laser diode and microprocessor unit. The apparatus used a InGaAlP laser diode for laser medical therapy and was designed for a pulse width modulation type to increase stimulation effects. To raise the stimulus effect of the human body, the optical irradiation frequency could be set up. The study has executed in-vivo experiment by employing our own developed laser diode irradiation system to investigate the effects of the InGaAlP laser diode irradiation on the wound healing as a preliminary study aimed at the application of InGaAlP laser diode to wound healing of human skin injury. The study cut out whole skin layers of Sprague-Dawley rat on the back part in 1 cm circle and observed developing effects after executing light irradiation for 9 days, and in result it is found that the light irradiation rat showed earlier wound healing than non-irradiation rat during the experimental period. In addition, there are some differences found regarding the healing process between laser diode irradiated rats and non-irradiated ones.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.66-74
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• 1999

InAlGaAs/InGaAs HBTs with the various emitter junction gradings(xf=0.0-1.0) and the modified collector structures (collector- I;n-p-n, collector-II;i-p-n) are simulated and analyzed by HMC (Hybrid Monte Carlo) method in order to find an optimum structure for the shortest transit time. A minimum base transit time($ au$b) of 0.21ps was obtainsed for HBT with the grading layer, which is parabolically graded from $x_f$=1.0 and xf=0.5 at the emitter-base interface. The minimum collector transit time($\tau$c) of 0.31ps was found when the collector was modified by inserting p-p-n layers, because p layer makes it possible to relax the electric field in the i-type collector layer, confining the electrons in the $\Gamma$-valley during transporting across the collector. Thus InAlGaAs/InGaAs HBT in combination with the emitter grading($x_f$=0.5) and the modified collector-III showed the transit times of 0.87 psec and the cut-off frequency (f$\tau$) of 183 GHz.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.161-165
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• 2005

We investigated selective dry etching of GaAs over AlGaAs and InGaP in high density planar inductively coupled $BCl_3/SF_6$ plasmas. The process parameters were ICP source power (0-500 W), RE chuck power (0-30W) and gas composition $(60-100\%\;BCl_3\;in\;BCl_3/SF_6)$. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching. $BCl_3/SF_6$ selective etching of GaAs showed quite good results in this study. Selectivities of GaAs $(GaAs:AlGaAs\~36:1,\;GaAs:InGaP\~45:1)$ were superior at $18BCl_3/2SF_6$, 20 W RF chuck power, 300 W ICP source power and 7.5 mTorr. Addition of $(5-15\%)SF_6\;to\;BCl_3$ produced relatively high selectivities of GaAs over AlGaAs and InGaP during etching due to decrease of etch rates of AlGaAs and InGaP (boiling points of etch products: $AlF_3\~1300^{\circ}C,\;InF_3>1200^{\circ}C$ at atmosphere) at the condition. SEM and AFM data showed slightly sloped sidewall and somewhat rough surface$(RMS\~9nm)$. XPS study on the surface of processed GaAs proved a very clean surface after dry etching. It shows that planar inductively coupled $BCl_3/SF_6$ plasmas could be a good candidate for selective dry etching of GaAs over AlGaAs and InGaP.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.166-166
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• 2010

산업 전반에 걸쳐 중요한 광원인 808 nm 대역의 레이저 다이오드 제작에는 현재 InGaAsP/InGaP/GaAs 및 InGaAlAs/GaAs 양자우물을 이용하여 제작되고 있다. 이는 양자우물과 이를 둘러싸는 장벽물질간의 band-offset이 적어 효율적인 고출력 레이저 다이오드의 제작에 어려움이 있기 때문에 강한 캐리어 구속 효과를 지니는 양자점을 사용하는 것이 고출력 레이저 다이오드를 제작할 수 있는 방법이다. 실험에 사용된 InAlAs 양자점은 Riber사의 compact21 MBE 장치를 사용하여 성장하였으며 GaAs기판을 610도에서 가열하여 표면의 산화층을 제거하고 580도에서 약 100 nm 두께의 GaAs 버퍼층 및 30 nm 두께의 $Al_{0.4}Ga_{0.6}As$층을 성장하였다. GaAs 기판의 온도를 내린 후 migration enhanced epitaxy 방법을 사용하여 InAs 및 AlAs를 번갈아 주입하여 성장하였다. InAlAs 양자점의 성장 중에 InAlAs의 양, 성장 온도, As flux량 및 As 분자 상태 변화 등 다양한 조건을 변화 시켜 샘플을 성장시켰다. 그 결과 기판 온도가 600도이며 As4 flux가 $1\;{\times}\;10^{-6}\;Torr$ 조건하에서 성장한 InAlAs/AlGaAs 양자점이 양질의 808 nm의 파장 대역을 얻을 수 있었다.

• Journal of the Korean Institute of Navigation
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• v.15 no.3
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• pp.99-106
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• 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.