진공증착 법으로 제작한 $WO_{3}$/CdS 박막의 가시광 광 변색의 에너지 전환

김근묵,김명욱,Kim, Keun-Mook,Kim, Myung-Wook 한국반도체디스플레이기술학회 2005 반도체디스플레이기술학회지 Vol.4 No.1

Tungsten oxide($WO_{3}$) is suitable to materials for photochromic window in the visible region. The resistivities of CdS, $WO_{3}$, and $WO_{3}$/CdS films prepared by thermal evaporation method were $4.61\times 10\^{3}$, $7.59\times10^{3}$, and $6.29\times10^{3}$ $\omega$ cm. And x-ray diffraction patterns of CdS, $WO_{3}$/CdS films showed a preferred orientation of hexagonal(002), and the monoclinic(020) structure, respectively. The optical transmission were measured that the cut-on wavelength were 510nm, 380nm for CdS and $WO_{3}$ films respectively, and the transmission spectrum of $WO_{3}$/CdS was shifted into the visible region. Photoluminescence(PL) spectra showed the two peaks at 2.8 eV and 3.2 eV for the as-grown sample($WO_{3}$/CdS ($500{\AA}$), but the other sample($WO_{3}$/CdS ($1000{\AA}$)) had a peak energy value of 2.8 eV. The photochromism of $WO_{3}$/CdS films showed that the excitation of electron-hole pairs and subsequent coloration is shifted into visible-light range. And the spectral behavior of coloration turned out to be proportional to the excited electron-hole pairs creation rate of CdS film. This result is interpreted in terms of charge carrier injection from the CdS-layer into the $WO_{3}$ films. We found a value of about 2.8 eV of $WO_{3}$/CdS film which is somewhat higher than peak energy of 2.54 eV using CBD prepared by Bechinger et. al.

결합 모드이론에 의한 2-port형 탄성표면파 공진기의 설계

李東旭(Dong-Wook Lee),黃金燦(Keum-Chan Whang),金根默(Keun-Mook Kim) 대한전기학회 1987 전기학회논문지 Vol.36 No.1

Cu/As^(x)Se1^(-x) 유리 반도체의 특성

金根默 水原大學校 2005 論文集 Vol.23 No.-

Cu/AsSe glassy semiconductor fabricated by thermal evaporation method were investigated for the dependence of thickness ratio, temperature, and response time of the Cu/semiconductor hetero-layers. The thickness ratio of Cu-AsSe system being equal to 8 the limiting rates of Cu-diffusion into the AsSe semiconductor layer are reached. The dependence of surface resistance of the Cu/AsSe sample for the ratio of dAsSe/dCu= 8. which is above critical and equals to 270 K. And the response time of the same sample at 340 K. and 310 K are measured 7 sec and 30 sec respective.

공기중 열처리에 따른 CdS 박막의 PL 특성

김근묵 수원대학교 자연과학연구소 2001 자연과학논문집 Vol.4 No.-

CdS thin films prepared by vacuum thermal evaporation have been studied SEM, X-ray diffraction, 4-point probe method, and temperature dependence photoluminescence(PL) from 10K to 300K temperature. The results of SEM and XRD measurement of heat-treated CdS films showed the 'CdO' defects and 33° and 38° peaks of X-ray diffraction. The temperature dependence photoluminescence of the edge emission(EE) of heat-treated samples at 550℃ varied from 2.51eV(10K) to 4.2eV(300K).

WO₃박막에서 CdSSe-interlayer의 광학적 효과

김근묵 수원대학교 기능성생명소재연구소 2007 자연과학연구논문집 Vol.6 No.1

As the color ation phenomena depending upon the wavelength of a tungsten oxide is suitable to a material for photochromic windows and can be used for the windows of automotives and aircrafts, since it was presented by S. K. Deb in 1973 many researches have been under way in this area. In this research, despite the merit that WO₃ materials the high energy gap of 3.25eV and the transparent and strong light absorption state the absorption center has a bias toward the near UV region, and therefore in order to move the absorption center to the visible region, using the heat vapor deplation method a CdSSe-interlayer was inserted and vapor deposited, by which a photochromic thin film has been produced. As a result of X-Fay diffraction measurement, the structure of CdSSe was hexagonal and at 22.9˚ there appeared a diffraction line corresponding to a plane (020) but WO₃ showed an amorphous state. Therefore it is thought that it may be possible to produce a discoloration element that is moved to the visible region from the UV region by making use of the CdSSe-interlayey for the windows of photochromism.

Hg_(1-x) Cd_x T_e의 생장특성 및 전기적 성질

金根默,郭泳稙 수원대학교 산업기술연구소 1986 산업기술연구소논문집 Vol.1 No.-

적외선 검출용으로 사용되는 Hg_(1-x)Cd_xTe (MCT) 결정 (χ=0.2)을 vertical zone melting (VZM) 법과 traveling heater method(THM)으로 생장시키어 그 특성을 조사 연구하였다. 생장된 결정의 조성χ는 밀도측정, X선회절법, 적외선 투과 및 electron microprobe analysis (EMA)로 측정하였다. THM이 덩어리 결정생장방법중 가장 우수한 방법으로 평가되었으며 이 방법으로 생장된 결정은 출방향으로 약 ⅔ 정도가 χ=0.20±0.005㏖이며 경방향 Δχ=0.002의 조성을 가짐을 EMA 및 적외선 투과측정으로 확인하였다. 생장된 결정은 보통 P형이며 Hall효과측정으로 77K에서 Hall이동도와 carrier농도가 각각 200㎠/v·sec, 6×10_15㎝^-3이었다. 260℃에서 100시간 Hg증기압 하에서 열처리한 시료는 Hall이동도와 carrier 농도가 각각 4×10^4㎠/v·sec, 2×10^15㎝^-3이었다. 가장 좋은 결과는 300℃, 100시간동안 열처리한 시료의 경우는 Hall이동도와 carrier농도가 77K에서 1.44 ×10^5㎠/v·sec, 4.58×10^15㎝^-3이어서 적외선 검출용으로 적합한 것으로 평가되었다. Infrared detecfing Hg_(1-x) Cd_xTe(MCT) crystals (x=0.2) were grown by vertical zone melting (VZM) and traveling heater method (THM) and characterized. The composition χ of grown cystals were evaluated by denisty measurement, X-ray diffraction, infrared transmission and electron microprobe analysis (EMA) method. Among the growth methods, THM was found to be the most superior method to obtain homogeneous crystal both in growing axial and radial directions. With this method the composition χ of a crystal revealed that about 2/3 of the axial length was χ=0.2±0.005mol and the radial variation Δχ=0.002mol confirmed by EMA and IR-transmission measurements. As grown crystal usually showed s-type conductivity, Hall mobility and carrier concentration at 77K were 200㎠/v·sec, 6×10^18㎝^-3 respectively. After annealing(260℃, 100hr) in Hg-vapor they showed n- Type conductivity and 4×10^4㎠/v·sec, and 2×10^15㎝^-3 respectively. The best results was found to be 1.44×10^5㎠/v·sec, 4.58×10^15㎝^-3 after annealing(330℃, 100hrs), this results were comparable with commercial products of MCT.

적외선 소자의 광흡수 특성

김근묵 수원대학교 기초과학연구소 1995 基礎科學論文集 Vol.4 No.-

The typical infrared detectors as a function of wavelength are PbS of the 1-3㎛, InSb of 3-5㎛ and Si and Ge for impurites types materials. But its properites is not better than HgCdTe at the time constant and response temperature and response wavelength range. The HgCdTe materials for a IR-detector at wavelength range 3-5㎛ for composition x= 0.3 and 8-14㎛ for composition x= 0.2 at 77K and 300K respectvily. The Hall data of HgCdTe grown by THM was p type and the energy gap(E_g) were measured by optical absorption coefficient at composition range of 0.197≤x≤0.300.

진공증착법으로 생장된 CdSSe 박막의 특성

金根默 水原大學校 2002 論文集 Vol.20 No.-

CdS, CdSe, and CdSSe thin films have been grown by vacuum evaporation method at substrate temperature of 65℃∼150℃. SEM analysis of CdSSe showed that thin films deposited at temperature of 115℃ and 150℃ exhibited crystallinity with pyramidal and conical shapes. XRD revealed that CdS, CdSSe films exhibited hexagonal structure with (0 0 2) orientation at 26.75,˚ 25.60,˚ 26.10˚ respectively. In the PL spectra of Cds and CdSSe, the band edge emission peaks at 2.42eV and 2.14eV, and the deep center of 1.65eV and 1.4eV due to Cd-vacancy were observed at the temperature of 10K.

CdS/InP 태양전지에 관한 연구

김근묵 수원대학교 기초과학연구소 1992 基礎科學論文集 Vol.1 No.-

CdS/InP solar cells are fabricated and characteristics are investigated. The current-voltage characteristics measured reveals the knee voltage and the breakdownvoltage to be 1.0 volt and 11 volts. And the spectral respons of photovoltage are nearly uniform form 500 nm to 1㎛ range. The photocurrent-photovoltage curve obtained short curicut current density, J_sc and open curcuit voltage, V_oc 5 ㎃/㎠ 0.5 volt under the irradiation of 50 ㎽/㎠ shows the filling factor 0.6 and power conversion efficiency 1.2 % respectively.

WO₃/CdS 박막의 가시광 포토크로믹

김근묵 水原大學校 2004 論文集 Vol.22 No.-

텅스텐 산화물(WO₃)은 파장에 따른 포토크로믹 현상(photochromic effect)이 잘 나타나는 재료로써 자동차 항공기 윈도우나 스마트 윈도우 등에 이용된다. 본 연구에서는 열 증착(thermal evaporation)법으로 WO₃/CdS/glass 구조의 박막을 제작하여 XRD, 전자현미경(SEM)으로 물성을 살펴보고 4-point probe 법에 의한 전기적 특성 및 광 투과, PL 측정에 의한 광학적 특성을 조사하였다. WO₃ 박막 사이에 형성된 CdS-interlayer 효과는 자외선(UV) 영역에서 가시광선 영역으로 변환된 포토크로믹(PC) 특성 결과를 얻었다. Tungsten oxide(WO₃) is suitable material for photochromic windows; automotive, aircraft, and smart windows. In this study, we prepared WO₃/CdS/glass structure thin films by thermal evaporation method were investigated X-ray diffraction, scanning electron microscope(SEM), 4-point probe measurement, optical transmittance, and photoluminescence(PL) measurements. The results of formation of CdS-interlayer underneath WO₃ films the sensitivity of photochromic effect is shifted from near-UV wavelength range to the visible light.