Self-activated CdS와 CdS: Mn 형광체의 자외선에 의한 발광

유평렬 順天大學校 1987 論文集 Vol.6 No.1

A study has been made for the photoluminescence of cadmium sulfide phosphors. The samples of SA CdS. CdS: Mn Phosphors are prepared by firing at 850℃ for an hour in nitrogen gas. In the case of SA CdS Phosphors, there are two different origins for the emission. that is, the first is due to deep centers (broad luminescence emission) and the second edge emission. It is also shown that the peaks at 565 nm may be attributable to the transition of Mn atoms from the first excited state ⁴T₁(⁴G) to the ground state ??A₁(??S) due to energy transfer in CdS:Mn Phosphors. The separation in energy level between ⁴T₁for Mn₂+ in zine sulfide crystal is about 9,313 cm-¹ at 19K and 250K.

진공, 공기, 카드뮴 분위기에서 열처리한 황화카드뮴 광전도셀 제작 및 Sensitivity와 Response time 특성

유평렬 순천대학교 기초과학연구소 1991 基礎科學硏究誌 Vol.2 No.-

승화방법으로 황화카드뮴 단결정을 성장하였다. 결정 모양은 원추형이고 직경 17㎜, 길이 17㎜ 이었다. 진공, 공기, 카드뮴 분위기에서 열처리한 후 황화카드뮴 광전도셀을 제작하였다. 각 광전도셀의 감도는 γ_vac = 0.95, γ_air = 0.82, and γ_Cd = 1.61 이었다. 반응시간을 측정한 결과 상승시간은 RT_vac = 4.1 ㎲, RT_air = 6.0 ㎲, RT_Cd = 7.0 ㎲ 이고, 소멸시간은 DT_vac = 70 ㎲, DT_air = 3.1 ㎲, DT_Cd = 90 ㎲ 이었다. The single crystal of cadmium sulfide was grown by sublimation method. The shape of the crystal was cone type and the diameter was 17㎜, the length 17㎜. The CdS Photoconductive cells annealed in vacuum, air, and cadmium atmospheres were fabricated. The sensitivities of CdS photoconductive cells annealed in vacuum, air, and cadmium atmospheres are γ_vac = 0.95, γ_air = 0.82, and γ_Cd = 1.61, respectively. The rise times of CdS photoconductive cells are RT_vac = 4.1 ㎲, RT_air = 6.0 ㎲, and RT_Cd = 7.0 ㎲ and the decay times are DT_vac = 70 ㎲, DT_air = 3.1 ㎲, and DT_Cd = 90 ㎲ at the light level of 20 Lux, respectively.

$Cu_2/CdS$ 태양전지 제작 및 그 특성연구

유평렬,김현숙,이재윤,강창훈,박은옥,정태수,김택성,양동익,신영진 한국결정성장학회 1997 韓國結晶成長學會誌 Vol.7 No.2

The sing1e crystal of cadmium sulfide was grown by vertical sublimation method. The lattice constants of CdS single crystal by extrapolation method are $a_0=4.139\AA$ and $c_0=6.719\AA$, respectively. The $Cu_2$S/CdS solar cell was fabricated using the single crystal of cadmium sulfide and the CuCl solution. The light- to- dark JV cross over effect of the $Cu_2$S/CdS solar cell was measured after annealing for 2 minutes at $250^{\circ}C$ in air atmosphere. The values of Voc, Jsc, Vop, FF, and efficiency are 0.40 volt, $4.2mA/\textrm{cm}^2$, 0.31 volt, $3.8mA/\textrm{cm}^2$, 0.68 and 3.8 %, respectively. The spectral response of the solar cell shows the peaks at 498 nm (2.49 eV) and 585 nm (2.12 eV). 수직승화방법을 이용하여 시료의 용융점 미만의 온도에서 CdS 단결정을 성장하였다. 분말법을 이용한 X-ray 실험으로부터 구한 CdS 단결정의 격자상수 값은 $a_0=4.139\AA$, $c_0=6.719\AA$이었다. 성장된 CdS 단결정과 CuCl 용액을 사용하여 $Cu_2$S/CdS 태양전지를 제작한 후 2분 동안 공기중에서 $250^{\circ}C$로 열처리한 후 light-to-dark J-V cross over effect를 측정하였다. 측정된 Voc, Jsc, Vop와 fill factor값은 각각 0.40 volt, $4.2mA/\textrm{cm}^2$, 0.31 volt,$3.8mA/\textrm{cm}^2$, 0.68이었으며, 효율은 3.8 %를 나타내었다. 제작된 태양전지의 spectral response는 광발광 실험으로부터 498 nm (2.49eV)와 585 nm (2.12 eV)에서 그 peak가 나타남을 확인하였다.

고주파 반응성 스퍼터링에 의한 p형 ZnSe/GaAs 박막성장 및 특성연구

유평렬,정태수,신영진 한국결정성장학회 1999 한국결정성장학회지 Vol.9 No.1

고주파 반응성 스퍼터링에 의하여 ZnSe/GaAs 박막을 성장하였다. 박막성장을 위한 본 시스템에서의 최적조건을 찾기 위하여 Ar 압력, sputter 입력전력, 기판온도, 기판과 target 간격의 변화 등을 시도하였다. 성장된 결정의 표면과 격면을 전자현미경으로 관찰했을 때 표면이 균일하게 성장되었으며 기판과 박막의 계면이 평활함을 알 수 있었다. DCRC 측정에 의해 격자 부정합에 의한 변형과 부정합률을 구했다. Photoluminescence 측정으로부터 질소를 주입하지않고 성장한 ZnSe/GaAs 시료는 bound exciton $I_2$세기가 $I_1$보다 우세하게 나타났고 bound exciton $I_2$은 깊은 받개준위인 $I_1\;^d$를 나타냄을 확인할 수 있었다. 성장 중에 질소를 주입한 ZnSe/GaAs 시료에서는 $I_1$ 봉우리가 $I_2$봉우리보다 세기가 매우 컸으며 반폭치값도 작게 나타났다. 이때 bound exciton $I_1$의 근원은 질소의 doping으로 인하여 방출되는 봉우리이며 p형 ZnSe/GaAs 박막으로 성장되었음을 확인하였다. The ZnSe/GaAs epilayers were grown by RF reactive sputtering. In order to obtain the optimum condition of the growth, we have studied the dependence of Ar pressure, input power of sputter, temperature of substrate, and the distande between substrate and target. Through the observation of the grown epilayer via electronic microscope, we confirmed that the layer's surface was uniform and the boundary of the substrate and the layer was well defined. The defotmation of lattice distortion and the distortion ratio were obtained by DCRC measurements. From mrasurements of photoluminescence, in the ZnSe/GaAs sample without injection of $N_2$gas, we found that the intensity of bound exciton $I_2$is stronger than that of $I_1$and the bound exiton $I_1$represents the deep acceptor level, $I_1\;^d$. On the other hand, in the ZnSe/GaAs sample with injection of$N_2$gas, the peak of$I_1$ was much higher than that of the $I_2$and the half width appeared to be narrow. We concluded that the p-type of ZnSe/GaAs epilayer was grown successfully, because of stronger peak of the bound exciton $I_1$due to the $N_2$dopping.

Cu_2S/CdS 태양전지 제작과 그 특성 연구

유평렬 순천대학교 기초과학연구소 1990 基礎科學硏究誌 Vol.1 No.-

The single crystal of cadmium sulfide was grown by vertical sublimation method. The lattice constants of CdS single crystal by extrapolation method are a_0=4.1387Å and c_0=6.7188Å respectively. The Cu_2S/CdS solar cell was fabricated using the single crystal of cadmium sulfide and the CuCl solution. After annealing for 2 minutes at 250℃ in air atmosphere, the Light-to-Dark JV cross over effect of the Cu_2S/CdS solar cell was measured. The values of Voc, Jsc, Vop, Jop, FF, and efficiency are 0.38volt, 4㎃/㎠, 0.30volt. 3.7㎃/㎠, 0.73, and 3.7%, respectively. The spectral response of the solar cell show the peaks at 498㎚(2.49eV) and 585㎚(2.12eV).

Cds 광전도쎌의 Maximum Allowable Power Dissipation 및 Photoconductivity Gain

유평렬 順天大學校 1991 論文集 Vol.10 No.1

황화카드뮴 단결정을 성장하여 광전도쎌로서의 응용성을 알아보기 위해 최대 허용 전력소비와 광전도도 이득에 대해 연구하였다. 300Lux, 500Lux, 800Lux의 조도에서의 실험을 통하여 구한 각 시료의 최대 허용 전력소비의 연구 결과 공기중에서 열처리한 광전도쎌의 MAPD값이 295mW로 가장 좋은 특성을 보였다. 또한 photo-Hall 효과 측정 및 반응시간의 측정으로 광전도 이득 값을 계산한 결과 진공중에서 열처리한 광전도쎌의 이득이 18.8로 광감도가 가장 우수하였다. Crystal growth of cadmium sulfide by the subimation method was carried out using two-zone vertical electric furnace. The CdS:air, CdS:vacuum, CdS:Cd photoconductive cell was fabricated, and then its characteristics of maximum allowable power dissipation and photoconductivity gain were investigated by photo-Hall effect, response time, and illumination current-voltage measurements etc. The values of MAPDair, MAPDvac, and MAPDcd were 295mW, 126mW, and 8.6mW, respectively. The values of the photoconductivity gain Gair, Gvac, and Gcd were 13.5, 18.8, and 9.3, respectively.

Vapour phase transport 방법에 의한 CdS 단결정 성장 및 광전류와 광발광 특성

유평렬 順天大學校 1988 論文集 Vol.7 No.1

Crystal growth of cadmium sulfide by the halogen transport method was carried out using iodine as a transporting agent in a sealed ampoule kept at temperatures of 700℃ and 900℃ for the growth part and the source part, respectively. The lattice constants of the grown CdS(PL A, B) single crystal were measured to the a??=4.1380 Å and c??=6.7178 Å,while CdS(PC C, D) single crystal were measured to thd a??=4.1377 Å and c??=6.7207 Å. Photoluminescence emission spectra of the grown samples show a prominent G?? line peak, whereas its photocurrent spectra show a peak at 512nm {CdS(PLA)}, 502.5nm {CdS(PL B)}, 500nm {CdS(PC C)}, and 590nm {CdS(PC D)} due to an intrinsic transition peaks at 760nm(1.63 ev) and 1580nm (0.79 ev) by the infrared quenching effect.

선택적으로 doping된 AlGaAs/GaAs이종접합 구조에서 에너지 띠 구조와 전자수송

최춘태,유평렬 順天大學校 1995 論文集 Vol.14 No.1

Two-dimensional electron gas transport properties in selectively doped n-AlGaAs/GaAs heterojunctions grown by MBE are studied. Hall data measurements are done in the temperature range of from 3.6 to 310K and in the spacer thickness of 170Å. Scattering mechanisms included two subbands are assessed through a numerical iterative solution of the Boltzmann equation and compared with the experimental Hall data. Temperature dependence of the measured Hall mobility at low temperature is shown to be good agreement with the theory of scattering mechanisms included two subbands, whereas the high temperature data disagree with existing theory of polar optical phonon scattering.

lodine을 촉매로한 기상성장 방법에 의한 CdS 단결정 성장 및 Hall Effect 특성

유평렬,신영진,정태수 順天大學校 1988 論文集 Vol.7 No.1

Crystal growth of cadmium sulfide by the halogen transport method was carried out using iodine as a transporting agent in a sealed ampoule kept at temperatures of 700℃ and 900℃ for the growth part and the source part, respectively. The lattice constants of the grown CdS(PL A, B) single crystal were measured to the a??=4.1380 Å and c??=6.7178 Å,while CdS(PC C, D) single crystal were measured to the a??=4.1377 Å and c??=6.7207 Å, The electron carrier concentrations and Hall mobility were also measured using the van der pauw method at the temperature of 293k and below, and their values are about ∼10²³m-³ and about 10-²∼10-³m²/v·s, respectively.

ZnSe 단결정 성장과 전기-광학적 특성

유평렬,김택성 順天大學校 1991 論文集 Vol.10 No.1

수송물질로 요오드를 사용하여 기상 수송방법으로 ZnSe 단결저을 성장 하였다. 성장부분과 시료부분의 온도는 각각 815℃와 1065℃로 하였다. Van-der Pauw방법으로 측정된 전하농도와 Hall 운동도는 실온에서 각각 ?? ??,??/v-s order 정도 이었다. 성장된 sample의 PL방출 스펙트럼은 실온에서 520nm의 peak를 이루었으며 Lambe-Klick모델에 따르는 green 발광으로 분석 되었다. Crytal growth of zinc selenide by vapour phase transport method was carried out using iodine as a transporting agent in a sealed ampoule kept oat temperatures of 815℃ and 1065℃ for the growth part and source part, respectively. The electron carrier concentration and Hall mobility were measured of using Van der Pauw method at room temperature and their values are about ∼?? ?? and about ∼??/v-s, respectively. Photoluminescence emission spectra of the grown sample were peaked at 520nm at room temperature.