• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1880-1885
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• 2016

This study aims to design a zonal lumen for parking garage LED lightings of a slim appearance and 20 W/2,000 lm capacity and to fabricate a lighting luminaire accordingly. The frame is of a one-dimensional bar type with a reverse V-shaped section, with LED chips arranged along both sides. To maximize the $60^{\circ}$ to $80^{\circ}$ zonal lumen, the geometric structure was designed with the apex of the reverse V-shaped section at $40^{\circ}$ and both sides at $70^{\circ}$. As for the LED light source, focusing lenses with narrower full-width half-maximum (FWHM) in luminous intensity were used. A ray-tracing simulation method was utilized for the zonal lumen simulation of the given structure. An actual hardware of luminaire based on the simulation results was fabricated and characterized. The suggested model is meant to develop LED lightings with a proper level of zonal lumen required in parking garages.

• 세라미스트
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• 제10권3호
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• pp.7-14
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• 2007

PbS QDs in glasses have attracted much attention due to the potentials for near-infrared applications. Growth of PbS QDs in the glass is discussed and size of PbS QDs formed in the glass can be tuned by varying the thermal treatment conditions. Hyperbolic-band approximation and four-band envelope function provide good simulation of the exciton energies of PbS QDs. Absorption and photoluminescence of PbS QDs was tuned into $1{\sim}2{\mu}m$ wave-length regime with large full width at half maximum photoluminescence intensity (>160 nm). Photoluminescence intensity of PbS QDs in the glasses was closely related to size of quantum dots, temperature, excitation and defects. Decrease in temperature shifted the photoluminescence bands to shorter wavelength and switched the photoluminescence from darkened state and brightened state.

• 한국결정성장학회지
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• 제8권1호
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• pp.124-130
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• 1998

양극반응 전류밀도를 변화시키면서 다공질 규소를 제작하여 라만산란을 관측하였다. 전류밀도가 증가함에 따라 라만신호는 520.5$\textrm{cm}^{-1}$에서 멀어졌으며, 봉우리의 반치폭이 증가하였다. 또한 전류밀도 증가에 따라 원통형 다공질 결정의 직경은 감소함이 계산되었으며, 길이가 길어짐을 AFM으로 관찰하였다.

• 센서학회지
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• 제13권4호
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• pp.277-281
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• 2004

$Hg_{1-x}Cd_{x}Te$ (MCT) was grown by hot wall epitaxy. Prior to the MCT growth, the CdTe (111) buffer layer was grown on the GaAs substrate at the temperature of $590^{\circ}C$ for 15 min. When the thickness of the CdTe buffer layer was $5{\mu}m$ or thicker, the full width at half maximum values obtained from the x-ray rocking curves were found to significantly decrease. After a good quality CdTe buffer layer was grown, the MCT epilayers were grown on the CdTe (111)/GaAs substrate at various temperatures in situ. The crystal quality for those epilayers was investigated by means of the x-ray rocking curves and the photocurrent experiment. The photoconductor characterization for the epilayers was also measured. The energy band gap of MCT was determined from the photocurrent measurement and the x composition rates from the temperature dependence of the energy band gap were turned out.

• 한국재료학회지
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• 제9권1호
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• pp.99-103
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• 1999

We investigated the crystalline behavior in active ion implanted silicon through Raman spectroscopy. Four a-Si(amorphous Si) peaks were observed that are related to the ion implantation induced a-Si layer. After the isochronical anneal(30min). and isothermal anneal($450^{\circ}C$), noticeable recovery of crystalline-Si peak at 519cm\ulcorner and peak center shift of the a-Si TO from 465cm\ulcorner to 480cm\ulcorner were observed by RNM(Random Network Model). By applying RNM and SCLM(Spatial Correlation Length Model), the peak center and FWHM(the Full Width at half Maximum) of a-Si were changed dramatically between T\ulcorner=$200^{\circ}C$ and 30$0^{\circ}C$. From the results, it can be said that there is an abrupt structural change at this temperature region.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.152-152
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• 2003

Hg$\sub$l-x/Cd$\sub$x/Te (MCT) was grown by hot wall epitaxy. Prior to the MCT growth, the CdTe (111) buffer layer was grown on the GaAs substrate at the temperature of 590$^{\circ}C$ for 15 min. When the thickness of the CdTe buffer layer was 5 $\mu\textrm{m}$ or thicker, the full width at half maximum values obtained from the x-ray rocking curves were found to significantly decrease. After a good quality CdTe buffer layer was grown, the MCT epilayers were grown on the CdTe (111) /GaAs substrate at various temperatures in situ. The crystal quality for those epilayers was investigated by means of the x-ray rocking curves and the photocurrent experiment The photoconductor characterization for the epilayers was also measured The energy band gap of MCT was determined from the photocurrent measurement and the x composition rates from the temperature dependence of the energy band gap were turned out

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1272-1280
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• 2001

SrS:Ce thin films for blue EL devices were prepared by Hot Wall Method and their crystallographic and optical characteristics were investigated by various methods. Deposition rates were increased with SrS cell temperature, but the rates were independent on substrate temperature and sulfur pressure. The optical and crystallographic characteristics were strongly affected by deposition rates. The band gap energies obtained by optical transmission spectra and Full Width at Half Maximum of (200) plane in X-ray diffraction patterns were found at 4.5-4.6eV and $0.22~0.26^{\circ}$, respectively. The photoluminescence from SrS:Ce thin tiles showed a greenish blue omission peaked at 470 and 540nm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.848-850
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• 2001

In this work, we investigated on the white-colored ribbon fiber synthesized from GaN powder. We convinced the formation of monoclinic phase $\beta$-Ga$_2$O$_3$from the X-ray diffraction pattern on ribbon fiber. The 10 K PL spectrum consisted with the strong emission band caused by self-activated optical center at 3.464 eV with the full-width at half maximum of 48 meV and the impurity related emission bands. Through this work, the optical properties and the electrical conductivity of $\beta$-Ga$_2$O$_3$, it will be useful for the fabrication of optoelctronic devices operating in visible spectrum region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.987-989
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• 1998

We demonstrate and characterize a volume holographic filter operating at $1.55{\mu}m$ region, which corresponds to the wavelength region of optical communication system. By changing recording times or the angle between writing beams. the reflectivity, the filtered wavelength, and the bandwidth of this filter can be controlled. A center wavelength of 1532.8 nm, reflectivity of 10.7% and a bandwidth with full width at half-maximum of 4.0nm are measured in our experiment.

• 한국진공학회지
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• 제8권4A호
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• pp.470-475
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• 1999

ZnS and ZnTe epilayers were grown on GaAs(100) GaP(100) substrates by hot-wall eitaxy. X-ray diffraction revealed that the epilayers have zinc-blende structure and were grown in (100) direction. The small values of the full width at half maximum (FWHM) of double crystal rocking curve (DCRC) showed high quality of the epilayers. From the thickness dependence of the FWHM of DCRC, the strain remaining in films is found to be due to the thermal expansion difference as well as due to the lattice mismatch.