http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
대면적 레이저 다이오드의 필라멘테이션과 α-factor
한일기,허두창,이정일,이주인,Han, Il-Ki,Her, Du-Chang,Lee, Jung-Il,Lee, Joo-In 한국광학회 2002 한국광학회지 Vol.13 No.4
Linewidth enhancement factor ($\alpha{-factor}$) 값이 2와 4인 두 종류의 1.55${\mu}m$ 다층양자우물(Multi-Quantum Well; MQW) 대면적 레이저 다이오드를 제작하였다. 제작된 레이저 다이오드의 far-field 측정 결과 $\alpha{-factor}$ 값이 4일 때 보다 2인 구조에서 반폭치(Full Width at Half Maximum; FWHM)와 필라멘테이션(filamentation)이 감소되었다. 주입전류의 증가에 따라 두 종류 모두 far-field의 FWHM의 증가 현상이 나타났고 이는 filament spacing이 감소하였기 때문으로 설명된다. 1.55 ${\mu}m$multi-quantum well (MQW) broad area laser diodes with different linewidth enhancement factors ($\alpha{-factor}$) of 2 and 4 were fabricated. The far-fields of the laser diodes were measured. It was observed that the full width at half maximum (FWHM) of the far-fields and the filamentations were reduced in the laser diodes for which the value of the $\alpha{-factor}$ was small. As injection current increased, the FWHM of the far-field also increased regardless of the a-factor. This phenomenon was explained by reduction of filament spacing as injection current increased.
Threshold Current Increase in GaAs/AlGaAs Quantum Cascade Lasers due to the Thickness Variation
한일기,Jeong, Jin-Wook,송진동,JungIlLee 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.4
GaAs/AlGaAs quantum cascade laser (QCL) epi-structures were grown and lased successfully at 77 K. The thickness variation during the growth sequence was measured by analyzing the transmission electron microscope pictures. The thickness of the epi-layer decreased by up to 80 90 % of its expected value. At least three times higher threshold current and shorter lasing wavelength, compared to the reference QCL, were shown. The decrease in the growth rate during the growth sequence is thought to be a possible reason for such a high threshold current and short lasing wavelength.
Study on Superluminescent Diodes Using InGaAs-InAsChirped Quantum Dots
한일기,Du chang Heo,송진동,이주인,Jung il Lee 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.2
We have fabricated superluminescent diodes (SLD) by using InGaAs-InAs chirped quantum dots (QD). The spectral bandwidth of the SLD was measured to be 170 nm. These results explain the possibility of QD-based SLD exceeding the performance of multi-quantum well-based ones.
GaAs/AlGaAs Quantum Cascade Laser에서 Deep Mesa 구조에 의한 문턱전류 감소
한일기,송진동,이정일,Han, Il-Ki,Song, Jin-Dong,Lee, Jung-Il 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.6
GaAs/AlGaAs based quantum cascade lasers were fabricated with two different types of i) the shallow mesa type which was etched up to above active region and ii) the deep mesa type which was etched through active region. While the threshold current density of shallow mesa type was $26-32\;kA/cm^2$, the one of deep mesa type was reduced drastically up to $13\;kA/cm^2$. Such lowered threshold current density at deep mesa type attributed to the reduction of current loss to the lateral directions. GaAs/AlGaAs 물질계를 기반으로 한 양자폭포레이저를 제작하였다. 양자폭포레이저는 활성층의 위까지만 식각된 shallow mesa 구조와 활성층까지 식각된 deep mesa 구조로 제작되었다. shallow mesa 구조의 경우 문턱전류 밀도가 $26-32\;kA/cm^2$이었지만 deep mesa 구조의 경우 문턱전류 밀도는 $13\;kA/cm^2$로 대단히 감소되었다. Deep mesa 구조에서의 문턱전류 감소는 측면 방향으로의 전류 손실이 감소되었기 때문으로 설명되었다.
High Power Laser Diodes/Superluminescent Diodes
한일기 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
The author's group has developed multiple quantum well (MQW)-based diraction-limited high power laser diodes and superluminescent diodes (SLDs). For example, 1.55-m InGaAsP tapered lasers with a maximum power of CW 2.45 W and a diraction-limited power of CW 1 W have been reported. The author and co-authors have also developed 1.55-m InGaAsP SLDs with an optical power of 20 mW and simultaneously 3dB bandwidth of 130 nm. The author presents recent results on the quantum dot (QD) structures and explains potential possibility of QD-based devices to prevail over the performances of MQW-based devices in terms of diraction-limited high power laser diodes and SLDs.
화학적 빔 에피탁시에 의한 평면구조에서의 InP/InGaAs 다층구조의 선택적 영역 에피 성장
한일기,이정일,Han, Il-Ki,Lee, Jung-Il 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.6
Chemical beam epitaxy 성장법으로 InP/InGaAs 다층구조의 선택적 영역 에피성장 (selective area epitaxy)을 하였다. <011> 방향에 평행한 직선패턴에서는 선폭이 작아지고, <01-1> 방향에 평행한 직선패턴에서는 선폭이 증가하는 현상이 나타났는데 이는 InGaAs의 <311>A와 B면이 <01-1> 방향에 평행한 직선패턴에서 성장되었기 때문으로 설명되었다. 성장속도가 $1\;{\mu}m/h$인 조건에서 5족 가스의 압력이 감소할수록 (100) 면 위에서 평평한 에피층이 성장되었는데 이는 5족 가스의 과포화현상에 의한 3족 원소의 표면이동으로 설명하였다. Selective area epitaxy of multiple-stacked InP/InGaAs structures were grown by chemical beam epitaxy. The width of top of the multiple-stacked InP/InGaAs layer which were selectively grown on the stripe lines parallel to the <011> direction was narrowed, while the width of top of the multiple-stacked InP/InGaAs layer on the stripe lines parallel to the <01-1> was widen. This difference according to the <011> and <01-1> direction was explained by the growth of InGaAs <311>A and B faces on the (100) InP surface on the stripe lines parallel to the <01-1> direction. Under growth rate of $1\;{\mu}m/h$, top of the multiple-stacked InP/InGaAs was flattened as the pressure of group V gas was decreased. This phenomenon was understood by the saturation of group V element on the surface.
파장대역폭이 넓은 고휘도 발광소자를 위한 Chirped 양자점 구조의 광/전기 특성 분석
한일기,Han, Il-Ki 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.5
크기가 다른 양자점 (chirped 양자점) 구조에 대하여 전기발광 (Electroluminescence, EL) 특성과 광발광 (Photoluminescence, PL) 특성을 측정하고 비교 분석하였다. PL 특성에서는 양자점의 기저준위에 의한 피이크가 우세하게 나타난 반면, EL 특성에서는 여기준위에 의한 특성이 우세하게 나타났다. 이와 같은 특성비교로부터 기저준위도 EL 특성에 영향을 미칠 수 있도록 chirped 양자점 구조를 설계하면 파장대역폭이 더욱 넓은 고휘도 발광소자 개발이 가능할 것임을 제안하였다. We analyzed photoluminescence (PL) and electroluminescence characteristics of various chirped quantum dot structures. Peaks in EL curves were contributed by excited states of quantum dots (QD), while those in PL curves by grounded states. Based on these characteristics, we suggested that superluminescent diodes with wide spectral bandwidth may be developed if chirped QD structures are designed to make a contribution by ground states to EL characteristics.
Reactive Ion Etching에 의한 ITO/반도체 및 ITO/BaTiO3 구조의 선택적 에칭 특성
한일기,이윤희,김회종,이석,오명환,이정일,김선호,강광남,박홍이,Han, Il-Ki,Lee, Yun-Hi,Kim, Hwe-Jong,Lee, Seok,Oh, Myung-Hwan,Lee, Jung-Il,Kim, Sun-Ho,Kang, Kwang-Nham,Park, Hong-Lee 대한전자공학회 1995 전자공학회논문지-A Vol.32 No.1
Eteching characteristics of the Indium Tin Oxide (ITO), which is transparent conductor, was investigated with CH4/H2 and Ar as etching gases for the Reactive Ion Etching (RIE). With CH4/H2 for the etching gas, the highly selective etching characteristics for the ITO on GaAs was obtained. It was examined that the dominant etching parameter for the selective etchning of ITO on GaAs structure was the chamber pressure. But, the etching selectivity for ITO on InP was poor eventhough we tried systematic etching. RIE etching conditins using CH4/H2 gas was limited due to the formation of polymer on the substrates. In the case of Ar gas for the reactive gas, the selectivity of ITO on BaTiO3 was above 10. The etch rete of ITO was more sensitive to the etching parameters than that of BaTiO3, which was almost constant with different etching parameters.