• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.47-51
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• 2013

Current research trends of solar cells has focused on the high conversion efficiency and low-cost production technology. Passivation technology that can be easily adapted to mass production. Therefore, this study conducted experiments with aim of the following two methods for the fabrication of high-efficiency crystalline silicon solar cells. In the first task, an attempt is formation of local Al-BSF to a number of locally doped dots to increase the conversion efficiency of solar cells to reduce the loss of $V_{oc}$ overcome. The second major task, rear surface apply in $Al_2O_3/SiN_x$ stack layer, $Al_2O_3$ prominent negative fixed charge characteristics. As the result of task, Local Al-BSF and $Al_2O_3/SiN_x$ stack layer applied to the p-type single crystalline silicon solar cells, the average $V_{oc}$ of 644mV, $I_{sc}$ of 918mV and conversion efficiency of 18.70% were obtained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.480-485
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• 2011

ZnO is an n-type semiconductor with a wide band gap near 3.37 eV. It was known that ZnO films with a resistivity of the order of $10^{-4}\;{\Omega}cm$ is not easy to obtain. 1, 3, and 5wt% Si element were added into ZnO in ordre to improve the electrical and optical characteristics. The Si-doped ZnO (SZO) was grown on a glass substrate by radio frequency (RF) magnetron sputtering at the temperature range from 100 to $500^{\circ}C$. X-ray diffraction (XRD) patterns of SZO film showed preferable crystal orientation of (002) plane. It was confirmed that the lowest resistivity of the SZO films was $2.44{\times}10^{-3}{\Omega}cm$ and SZO films were significantly influenced by the working temperature. The average transmittance of the films was over 80% in the visible ranges.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.164-164
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• 2013

최근에 희토류 이온이 치환 고용된 실리케이트계 형광체를 발광 소자, 레이저, 광전 소자에 응용하기 위한 연구에 많은 관심이 집중되고 있다. 본 연구에서는 고상 반응법을 사용하여 초기 물질 CaO (99.99% 순도), SiO2 (99.99%), RE2O3 (RE=Sm3+, Tb3+, 99.9%)을 화학 적량으로 준비하여 활성제 이온 Sm3+과 Tb3+이온의 함량비를 0, 0.01, 0.05, 0.10, 0.20 mol로 변화시켜 Ca2SiO4:RE3+ 형광체를 제조하여 그것의 발광과 흡광 특성을 조사하였다. Sm3+ 이온이 도핑된 Ca2SiO4 형광체의 경우에, 발광 스펙트럼은 Sm3+ 이온의 함량비에 관계없이 모든 시료에서 602 nm에 피크를 갖는 강한 주황색 발광 스펙트럼, 상대적으로 발광 세기가 약한 569 nm에 정점을 갖는 황색 발광과, 652 nm와 711 nm에 피크를 갖는 적색 발광 스펙트럼이 관측되었다. Sm3+ 이온의 함량비가 0.01 mol 일 때 세 영역의 발광 스펙트럼의 세기는 최대값을 나타내었다. Sm3+ 이온의 함량비가 증가함에 따라 모든 발광 스펙트럼의 세기는 순차적으로 감소하였다. 이 현상은 농도 소광 현상에 기인함을 알 수 있었다. Sm3+ 이온이 도핑된 형광체 분말의 경우에, 주 흡광 스펙트럼은 Sm3+ 이온의 함량비에 관계없이 408 nm에서 관측되었으며, 이밖에도 상대적으로 흡광 세기가 약한 349 nm, 367 nm, 476 nm에서 흡광이 발생하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.408-409
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• 2007

Al-doped p-type ZnO films were fabricated on n-Si (100) and homo-buffer layers in pure oxygen at $450^{\circ}C$ by RF magnetron sputtering. Target was ZnO ceramic mixed with 2wt% $Al_2O_3$. XRD spectra show that the Al-doped ZnO thin films have ZnO crystal structure and homo-buffer layers are beneficial to Al-doped ZnO films to grow along c-axis. Hall Effect experiments with Van der Pauw configuration show that p-type carrier concentrations are ranged from $1.66{\times}10^{16}\;to\;4.04{\times}10^{18}cm^{-3}$, mobilities from 0.194 to $2.3cm^2V^{-1}s^{-1}$ and resistivities from 7.97 to $18.4{\Omega}cm$. P-type sample has density of $5.40cm^{-3}$ which is smaller than theoretically calculated value of $5.67cm^{-3}$. XPS spectra show that O1s has O-O and Zn-O structures and A12p has only Al-O structure. P-ZnO:Al/n-ZnO:Al junctions were fabricated by magnetron sputtering. V-I curves show that the p-n junctions have rectifying characteristics.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.503-508
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• 2010

$Eu^{2+}$-doped $\beta$-SiAlONs ($Si_{6-z}Al_zO_zN_{8-z}:Eu_y$) are recognized as promising phosphor materials to build an white LED for lighting application due to its excellent absorption/emission efficiency in the long wave length region. In this research, the fabrication of $\beta$-SiAlON:Eu plate phosphor by sintering was investigated with fixed Eu content(y) and varied composition of the host lattice(z). The addition of the activator $Eu_2O_3$ lead to enhanced densification by forming the transient liquid phase. The refinement of a composition by the calculated lattice parameter indicated that the measured composition of the fabricated specimens is nearly same to that of designed one. The single phase $\beta$-SiAlON:Eu plate with relative density of 96.4% was achieved by addition of 2 wt% CaO, which implies the possibility of full densification by adjusting the processing variables.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.529-532
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• 2007

Combined temperature programmed reaction (TPR) and infrared (IR) spectroscopic studies for Fischer- Tropsch reaction have been performed over Ru/SiO2 and Ru-Ag/SiO2 supported catalysts. Reaction of linearly absorbed CO with hydrogen starts at 375 K over Ru/SiO2 catalyst and reaches maximum at 420 K accompanied with an intensity decrease of linear CO absorption. The reaction with bridged absorbed CO peaks around 510-535 K. Addition of Ag yields mixed Ru-Ag bimetallic sites while it suppresses the formation of bridged bonded CO. Formation of methane on this modified surface occurs at 390 K and reaches maximum at 444 K. Suppression of hydrogen on the Ag-doped surface also occurs resulting in the formation of unsaturated hydrocarbons and of CHx intermediates not observed with Ru/SiO2 catalyst. Such intermediates are believed to be the building blocks of higher hydrocarbons during the Fischer-Tropsch synthesis. Linearly absorbed CO is found to be more reactive as compared to bridged CO. The Ag-modified surface also produces CO2 and carbon. On this surface, hydrogenation of CO begins at 390 K and reaches maximum at 494 K. The high temperature for hydrogenation of absorbed CO and C over Ru-Ag/SiO2 catalyst as compared to Ru/SiO2 catalyst is due to the formation of Ru-Ag bimetallic surfaces impeding hydrogen adsorption.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.575-579
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• 2008

Al-doped p-type ZnO films were fabricated on n-Si (100) and homo-buffer layers in pure oxygen at $450^{\circ}C$ of by RF magnetron sputtering. Target was ZnO ceramic mixed with 2 wt% $Al_2O_3$. XRD spectra show that the Al-doped ZnO thin films have ZnO crystal structure and homo-buffer layers are beneficial to Al-doped ZnO films to grow along c-axis. Hall Effect experiments with Van der Pauw configuration show that p-type carrier concentrations are ranged from $1.66{\times}10^{16}$ to $4.04{\times}10^{18}\;cm^{-3}$, mobilities from 0.194 to $2.3\;cm^2V^{-1}s^{-1}$ and resistivities from 7.97 to $18.4\;{\Omega}cm$. p-type sample has density of $5.40\;cm^{-3}$ which is smaller than theoretically calculated value of $5.67\;cm^{-3}$. XPS spectra show that Ols has O-O and Zn-O structures and Al2p has only Al-O structure. P-ZnO:Al/n-ZnO:Al junctions were fabricated by magnetron sputtering. V-I curves show that the p-n junctions have rectifying characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.173-173
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• 2009

높은 휘도를 갖는 $Eu^{2+}$가 도핑된 $Sr_3MgSi_2O_8$ 형광체는 고상반응법을 사용하여 합성하였다. 몰 비에 따른 조성을 정밀전자저울을 사용 무게를 칭량하여 에탄올을 용매로 하여 혼합, 건조 후 하소 온도는 $1000^{\circ}C$, 합성 온도는 $1200^{\circ}C$에서 $1400^{\circ}C$까지 $H_2$ 5% Ar 95% 환원분위기에서 소성 온도 별 결정상을 관찰하였고, 그 형태에 따라서는 Powder상태일 때와 Powder를 Press하여 bulk상태로써의 결정상의 변화를 연구하였다. 그 결과 분말상태와 성형을 가한 pellet의 두 가지 형태로 합성하여 비교한 결과 성형공정을 거친 시료의 경우가 분말 상태일 때 보다 좋지 못한 결정상이 관찰되었다. $Sr_3MgSi_2O_8$의 미세구조는 SEM으로 관찰하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1322_1323
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• 2009

The $V_{1.85}W_{0.15}O_5$ thin films deposited on Pt/Ti/$SiO_2$/Si substrates by RF sputtering method exhibited fairly good TCR and dielectric properties. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the annealing temperature. The dielectric constants of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were 38.11, with a dielectric loss of 1%, respectively. Also, the TCR values of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were about -3.45%/K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.101-102
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• 2006

금속을 도핑 함으로써 전기전도도가 향상될 것으로 생각되는 산화바나듐 나노선에 대하여 열처리 전후의 전기적 특성을 비교하였다. sol-gel 방법으로 만들어진 산화바나듐 xerogel($V_{1.66}Mo_{0.33}O_5{\cdot}nH_2O$)을 $Si_3N_4$ 절연막이 성장된 Si기판위에 분산시키고 Ti/Au으로 전극을 증착한 후 열처리 한 것과 하지 않은 두 시료의 전류-전압특성을 비교 분석하였다.