• Korean Journal of Materials Research
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• v.8 no.5
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• pp.419-423
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• 1998

The conditions for optimizing mass transport for making buried heterostructure (BH) InGaAsP/lnP lasers are discussed. The double heterostructure InGaAsP/lnP laser structures were grown by Liquid Phase Epitaxy (LPE) and etched into mesas. The active layer was selectively etched along [llO] and the mass transport was carried out in the LPE reactor to cover the sides of the active layer and form a BH structure. The threshold temperature for the appreciable mass transport is measured to be 670$670^{\circ}C$ when the holding time is set to 40 min. The width of the region re¬filled by mass transport is observed to increase as the temperature increases.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.1
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• pp.39-43
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• 2005

We proposed a structure for a 1.55 ㎛ strained separate confinement heterostructure (SCH) multi- quantum well (MQW) superluminescent diode (SLD), having a tapered active region. SLD was fabricated through a two-step procedure: the first step being metal organic chemical vapor deposition (MOCVD) and the second-step being liquid phase epitaxy (LPE). We used a 15 laterally tilted stripe and window region to suppress the lasing action of the SLD. The performance of the SLD showed output power of 11 mW with no lasing under 200 mA pulse driving. The full-width at half-maximum was 42 nm at 200 mA, 25℃.

• Journal of the Microelectronics and Packaging Society
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• v.4 no.2
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• pp.71-78
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• 1997

본 논문에서는 InGaAsP 에피막에서 도핑 농도와 에피막의 미세조직구조가 photoluminescence (PL) 스펙트럼의 위치 및 형상에 어떤 영향을 미치는가를 연구하였고, 그 결과를 설명하기 위해 가능한 모델을 제시하였다. InGaAsP 에피막(발진파장 ~1.3$\mu$m) 을 액상증착법(liquid phase epitaxy, LPE)으로 성장하여 9K에서 PL측정을 했을 때 InGaAsP 활성층 내 Zn 억셉터의 유무에 따라 PL 피크의 위치가 최대 30nm (24meV)까지 shift하고 피크의 선폭도 넓어지는 현사을 발견하였다. 이와같은 피크 분산현상은 inGaAsP 에피막이 유기금속 기상증착법으로 성장되거나 Zn로 고농도로 도핑되거나 고온에서 어닐링 될 경우 대폭 감소하였다. 이를 설명하기 위해 여러 가지 모델을 설정하여 실험을 하였으며 이 중 InGaAsP 에피막의 미세조직구조 특히 Spinodal 분해에 의한 조성이 모듈레이션과 Zn의 상호작용의 관계가 이 현상을 설명하는 데 가장 적절하다는 것을 밝혔다.

• Korean Journal of Materials Research
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• v.4 no.5
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• pp.600-607
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• 1994

Optimum exper~mental conditions were established for the growth of heteroepitaxial GaAs layers on InP using liquid phase epitaxy (LPE) technique. Results showed that the optimum growth temperature was $720^{\circ}C$ at a cooling rate of $0.5^{\circ}C$/min. Surface morphology of the grown layers significantly improved by addition of about 0.005wt% Se to the Ga growth melt, which effectively suppressed melt-back of InP substrates into the melt during the initial stage of growth. It was observed that the quality of GaAs layers also improved substantially when the substrates patterned with grating structure were used, as determined by the (400) double crystal X-ray diffraction. The transmission electron microscopy observation indicated t.hat the misfit dislocations interact with each other at the grating region, resulting in a lower dislocation density in the upper GaAs layer.

• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.337-342
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• 1997

We have investigated Mossbauer effect and emission properties of the Fe-doped GaAs grown by liquid phase epitaxy (LPE). The powder type of isotope $^{57}Fe$ was used as a dopant source in LPE-GaAs. From the analysis of Mossbauer effect the value of isomer shift, 0.303$\pm$0.018 mm/sec, is calculated at low temperature. This means that charge state of Fe ion in GaAs is 3+. The results of double crystal x-ray rocking curve (DCRC) and low temperature photoluminescence (PL) show the crystal quality of the epitaxial layers are good. Unusual luminescence peaks from the Fe-GaAs epitaxial layers appeared at emission energy of 0.99 eV and 1.15 eV. We attribute these emissions to Fe-acceptor related two deep radiative centers.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.168-171
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• 2005

Thickness optimization of heavily doped p-type seeding layer was studied to improve performance of thin film silicon solar cell. We used liquid phase epitaxy (LPE) to grow active layer of $25{\MU}m$ thickness on p+ seeding layer. The cells with p+ seeding layer of $10{\mu}m\;to\;50{\mu}m$ thickness were fabricated. The highest efficiency of a cell is $12.95\%$, with Voc=633mV, $Jsc=26.5mA/cm^2,\;FF=77.15\%$. The $P^+$ seeding layer of the cell is $20{\mu}m$, thick. As thicker seeding layer than $20{\mu}m$, the performance of the cell was degraded. The results demonstrate that the part of the recombination current is due to the heavily doped seeding layer. Thickness of heavily doped p-type seeding layer was optimized to $20{\mu}m$. The performance of solar cell is expected to improve with the incorporation of light trapping as texturing and AR coating.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.669-673
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• 2003

We fabricated a buried-ridge waveguide laser diode (B-RWG LD) which has more advantages for obtaining lateral single mode operation on the same ridge width and for the planarization of the device surface, compared to the conventional RWG LD. In this LD, the difference of the lateral effective refractive index can be controlled by the thickness of the InGaAsP layer which is grown on the active and the p-InP layers. The InGaAsP multiple quantum well was grown on a n-InP substrate by the CBE. The buried ridge structure was formed by selective wet etchings, followed by liquid phase epitaxy methods. The fabricated LD with the ridge width of 7 ${\mu}{\textrm}{m}$ showed a linear increase of the optical power up to 20 ㎽ without any kinks and a saturated output power of more than 80 ㎽. By measuring the far field pattern, we demonstrate that LDs with the ridge widths of 5 ${\mu}{\textrm}{m}$ and 7 ${\mu}{\textrm}{m}$ were operated in a lateral single mode up to 2.7I$_{th}$ and 2.4I$_{th}$, respectively.ely.