• 한국재료학회지
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• 제9권12호
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• pp.1155-1159
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• 1999

플라즈마 화학증착 (PECVD) 장비를 이용하여 $SnO_2$ 투명전도막이 피막된 유리기판 위에 p-SiC/i-Si/n-Si 이종접합 태양전지를 제작하였다. p-SiC 층의 증착중에 기체조성 x=$CH_4/\;(SiH_4+CH_4)$의 변화에 대한 태양전지의 광기전 특성을 관찰하였다. 기체조성(x)이 0~0.4의 범위에서 p-SiC 창층의 광학적 밴드갭의 증가로 인하여 태양전지의 효율은 증가하였으나, 그 이상의 기체조성에서는 p-SiC/i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 I-Si 층 사이에 I-SiC 완충층을 삽입함으로써 크게 감소하였다. 그 결과 유효면적이 $1cm^2$인 glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag 구조의 박막 태양전지는 100mW/$cm^2$ 조도 하에서 8.6%의 효율을 나타내었다. ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615)

• 한국세라믹학회지
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• 제33권8호
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• pp.915-920
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• 1996

콜로이드 졸-겔법에 의해 초미립자 mullite 분말을 제조하였다. Al2O3의 출발 물질로 aluminum isopropoxide $[Al(i-OC_3H_7)_3]$을, $SiO_2$ 출발 물질로 규산 나트륨으로부터 tetrahydrofuran(이후 THF로 약기함)으로 추출한 규산을 사용하였다. 규산 나트륨은 규산을 생성시키기 위하여 묽은 황산으로 산성화시킨 다음 THF로 추출하였다. Mullite 분말은 졸-겔법에 의해서 Si 추출율와 Na 제거율을 조사한 규산과 aluminum isopropoxide로 부터 합성되었다. THF로 추출한 규산의 불순물 함량은 0.04% 이하이었다. 합성된 mullite 분말은 $3Al_2O_3{\cdot}2SiO_2$ 조성을 갖고 불순물의 함량은 0.0462% 이하의 직경 $0.05{\mu}m$ 정도의 결정상이었다. EDS, XRD, TG/DSC, SEM, FT-IR, ICP, TEM등으로 mullite 분말의 특성을 조사하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1277-1279
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• 1994

In the structure of ZnO/nip-SiC: H/metal substrate amorphous silicon (a-Si:H) solar cells, the effects of inserting a rear textured ZnO in the p-SiC:H/metal interface and a graded bandgap buffer layer in the i/p-SiC:H have been analysed by computer simulation. The incident light was taken to have an intensity of $100mW/cm^2$(AM-1). The thickness of the a-Si:H n, ${\delta}$-doped a-SiC:H p, and buffer layers was assumed to be $200{\AA},\;66{\AA}$, and $80{\AA}$, respectively. The scattering coefficients of the front and back ZnO were taken to be 0.2 and 0.7, respectively. Inserting the rear buffer layer significantly increases the open circuit voltage($V_{oc}$) due to reduction of the i/p interface recombination rate. The use of textured ZnO markedly improves collection efficiency in the long wavelengths( above ${\sim}550nm$ ) by back scattering and light confinement effects, resulting in dramatic enhancement of the short circuit current density($J_{sc}$). By using the rear buffer and textured ZnO, the i-layer thickness of the ceil for obtaining the maximum efficiency becomes thinner(${\sim}2500{\AA}$). From these results, it is concluded that the use of textured ZnO and buffer layer at the backside of the ceil is very effective for enhancing the conversion efficiency and reducing the degradation of a-Si:H pin-type solar cells.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.1009-1014
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• 2012

Hydrogenated amorphous silicon (${\alpha}$-Si:H) layers deposited by plasma enhanced chemical vapor deposition (PECVD) are investigated for use in silicon hetero-junction solar cells employing n-type crystalline silicon (c-Si) substrates. The optical and structural properties of silicon hetero-junction devices have been characterized using spectroscopy ellipsometry and high resolution cross-sectional transmission electron micrograph (HRTEM). In addition, the effective carrier lifetime is measured by the quasi-steady-state photocoductance (QSSPC) method. We have studied on the correlation between the order of ${\alpha}$-Si:H and the passivation quality at the interface of ${\alpha}$-Si:H/c-Si. Base on the result, we have fabricated a silicon hetero-junction solar cell incorporating the ${\alpha}$-Si:H passivation layer with on open circuit voltage ($V_{oc}$) of 637 mV.

• 한국세라믹학회지
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• 제25권5호
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• pp.473-478
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• 1988

In order to obtain the high purity $\beta$-SiC powder that possesses the excellent sinterability and is close to the spherical shape, the carbon black was mixed into the composition of Si(OC2H5)4-H2O-NH3-C2H5OH which the monodispersed spherical fine particles is formed the hydrolysis of Ethylsilicate and the mixture was carbonized under an argon atmosphere. Particle shpae, size and the yield of $\beta$-SiC powder were investigated according to the molar ratio of carbon/alkoxide and variations of reaction temperature and reaction time. The results of this study are as follow ; 1) The yield of $\beta$-SiC gained from the reaction for one hour at 150$0^{\circ}C$ almost got near 100% and the particle size of $\beta$-SiC from the reaction for 15 hrs at 150$0^{\circ}C$ was 0.2${\mu}{\textrm}{m}$ on the average and close to the spherical shape agglomerate state. 2) When the molar ratio carbon/alkoxide is over 3.1 and the reaction occurs at 145$0^{\circ}C$ for 5hrs, the carbon content has not an effect on the kind of crystal of product.

• 한국결정성장학회지
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• 제7권2호
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• pp.216-223
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• 1997

출발물질로 aluminum iso-propoxide ($Al(OC_3H_7)_3$, AIP)를 사용하여 화학증착법으로 Si-wafer(100)위에 알루미나 박막을 증착하였다. 증착된 박막의 조성을 알아보기 위해 ESCA를 이용하였으며, SEM을 이용하여 박막의 형상 및 두께를 평가하였다. 그리고 굴절율 및 C-V 특성은 각각 ellipsometry와 HP4192A를 사용하였다. ESCA와 SEM의 분석결과에서 상압보다는 저압에서 막이 균일하고 조성이 잘 맞는 것을 알 수 있었으며 열처리를 통해 굴절율의 변화를 볼 수 있었다. 그리고 NMOS소자에서의 C-V특성을 개선하기 위해, $Al_2O_3$와 Si사이에 $SiO_2$층을 형성하는 것이 좋음을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제13권4호
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• pp.192-195
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• 2012

We reported diborane ($B_2H_6$) doped wide bandgap hydrogenated amorphous silicon oxide (p-type a-SiOx:H) films prepared by using silane ($SiH_4$) hydrogen ($H_2$) and nitrous oxide ($N_2O$) in a radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) system. We improved the $E_{opt}$ and conductivity of p-type a-SiOx:H films with various $N_2O$ and $B_2H_6$ ratios and applied those films in regards to the a-Si thin film solar cells. For the single layer p-type a-SiOx:H films, we achieved an optical band gap energy ($E_{opt}$) of 1.91 and 1.99 eV, electrical conductivity of approximately $10^{-7}$ S/cm and activation energy ($E_a$) of 0.57 to 0.52 eV with various $N_2O$ and $B_2H_6$ ratios. We applied those films for the a-Si thin film solar cell and the current-voltage characteristics are as given as: $V_{oc}$ = 853 and 842 mV, $J_{sc}$ = 13.87 and 15.13 $mA/cm^2$. FF = 0.645 and 0.656 and ${\eta}$ = 7.54 and 8.36% with $B_2H_6$ ratios of 0.5 and 1% respectively.

• 한국세라믹학회지
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• 제31권8호
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• pp.934-940
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• 1994

Fibers of ZrO2-SiO2 system were prepared from the hydrolysis and condensation of Si(OC2H5)4 and Zr(OnC3H7)4 with different H2O/alkoxide molar ratios. It was found that fibers could be drawn in the viscosity range of 1~100 poise from HCl catalyzed solutions with lower water contents of the mole ratio H2O/alkoxide, r 2. The fibrous gels were converted into the corresponding oxide glass fibers by heating at 80$0^{\circ}C$. Mechanical test was performed on E, A and 20ZrO2-80SiO2 glass fibers reinforced cement in order to investigate the flexural strength. The flexural strength value of 20ZrO2-80SiO2 glass fibers reinforced cement was greater than those of E and A. The chemical durability of the fibers in alkaline solutions increased with ZrO2 content. The weight loss due to the corrosion by 2N-NaOH solutions at $25^{\circ}C$ for 160 hours was about 0.31$\times$10-2 mg/dm2 for the 20ZrO2-80SiO2 glass fibers, which was superior to that of Vycor glass.

• 한국재료학회지
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• 제12권8호
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• pp.650-655
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• 2002

$SiO_2$ gels containing dispersed fine Te metal particles have been prepared by the sol- gel method using a starting solution containing Tetraethoxy Silane (Si($OC_2$ $H_{5}$ )$_4$), $H_2$O, Ethylalchol ($C_2$$H_{5}$OH), Nitric Acid ($HNO_3$) and Tellurium Tetracholoride ($TeCl_4$) in a several molar ratio. Gelling time of sols was about 3 days and viscosity of solution was very low about 2~3 cP for 3 days. Heat-treatments of the gel have been performed at 500, 700, 900, 1100 and $1300^{\circ}C$ for 1 hour, respectively. We have investigated TG-DTA, X-ray diffraction patterns and SEM of heat-treatmented gels. The size of Te fine particles dispersed in $SiO_2$ gel was about 0.8~1 $\mu\textrm{m}$ and the shape was almost quadrangle.

• 한국재료학회지
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• 제20권4호
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• pp.210-216
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• 2010

This paper investigates the dependence of a-Si:H/c-Si passivation and heterojunction solar cell performances on various cleaning processes of silicon wafers. It is observed that the passivation quality of a-Si:H thin-films on c-Si wafers depends highly on the initial H-termination properties of the wafer surface. The effective minority carrier lifetime (MCLT) of highly H-terminated wafer is beneficial for obtaining high quality passivation of a-Si:H/c-Si. The wafers passivated by p(n)-doped a-Si:H layers have low MCLT regardless of the initial H-termination quality. On the other hand, the MCLT of wafers incorporating intrinsic (i) a-Si:H as a passivation layer shows sensitive variation with initial cleaning and H-termination schemes. By applying the improved cleaning processes, we can obtain an MCLT of $100{\mu}sec$ after H-termination and above $600{\mu}sec$ after i a-Si:H thin film deposition. By adapting improved cleaning processes and by improving passivation and doped layers, we can fabricate a-Si:H/c-Si heterojunction solar cells with an active area conversion efficiency of 18.42%, which cells have an open circuit voltage of 0.670V, short circuit current of $37.31\;mA/cm^2$ and fill factor of 0.7374. These cells show more than 20% pseudo efficiency measured by Suns-$V_{oc}$ with an elimination of series resistance.