• 대한화학회지
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• 제38권1호
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• pp.1-7
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• 1994

알루미노인산염 족($AlPO_4-5$, BAPO-5, 그리고 SAPO-5)분자체의 구조 골격인 가교 $$T_1-OH-T_2$(T_1$ = Al, B 그리고 $T_2=$ P, Si) 안정성 및 가교 OH 그룹 이온성을 연구하기 위하여 반경험적 MNDO 계산 방법으로 연구하였다. 이러한 계산은 Al-OH-P, B-OH-P 그리고 Al-OH-Si덩어리 모델로써 실행하였다. Al-OH-P가교 모델에서 Al대신에 B원자를 치환할 때 B-OH-Si가교에서는 변형이 우선적으로 일어났으나, P 대신에 Si원자를 치환한 Al-OH-Si가교에서는 회전이 우선적으로 일어났다. 이러한 모델 덩어리에서 OH그룹 이온성 및 가교 안정성은 B-OH-P < Al-OH-P < Al-OH-Si 가교 순서로 증가하였다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1523-1528
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• 2014

Silicon quantum dots (Si QDs) were synthesized by etching silicon nanopowder with aqueous hydrofluoric acid (HF) and nitric acid ($HNO_3$). Then, the hydride-terminated Si QDs (H-Si QDs) were functionalized by 1- octadecene (ODE). By only controlling the etching time, the maximum luminescence peak of octadecylterminated Si QDs (ODE-Si QDs) was tuned from 404 nm to 507 nm. The average optical gap was increased from 2.60 eV (ODE-Si QDs-5 min) for 5 min of etching to 3.20 eV (ODE-Si QDs-15 min) for 15 min of etching, and to 3.40 eV (ODE-Si QDs-30 min) for 30 min of etching. The electron affinities (EA), ionization potentials (IP), and quasi-particle gap (${\varepsilon}^{qp}_{gap}$) of the Si QDs were determined by cyclic voltammetry (CV). The quasi-particle gaps obtained from the CV were in good agreement with the average optical gap values from UV-vis absorption. In the case of the ODE-Si QDs-30 min sample, the difference between the quasi-particle gap and the average optical gap gives the electron-hole Coulombic interaction energy. The additional electronic levels of the ODE-Si QDs-30 min and ODE-Si QDs-15 min samples determined by the CV results are interpreted to have originated from the Si=O bond terminating Si QD.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.224-229
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• 1999

The preparation and toughening of SiC-AIN solid solution from powder mixtures of $\beta$-SiC, AIN and $\alpha$-SiC by hot-pressing were studied in the 1870 to $2030^{\circ}C$ temperature range. The reaction of AIN and $\beta$-SiC(3C) powders causing transformation to the 2H(wurtzite) structure appeared to depend on hot-pressing temperatures and an additive of $\alpha$-SiC. For the composition of 49wt% SiC with 2 wt% $\alpha$-SiC and 47.5 wt% AIN47.5wt% SiC with 5 wt % $\alpha$-SiC at 203$0^{\circ}C$ for 1 h, th complete solid solutions with a single phase of 2H could be obtained. The appreciable amount of $\alpha$-SiC could develop the columnar inter-grains of 4H phase and the stable 2H phase with the relatively uniform composition and grain size distributions. The effect of $\alpha$-SiC on the phases present and compositional microstructures with columnar inter-grains was invetigated using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The fracture toughness and Vickers hardness of the hot-pressed solid solutions wre examined by the indentation-fracture-test method.

• 센서학회지
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• 제2권1호
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• pp.29-34
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• 1993

본 연구에서는 영상센서를 위해 a-Si : H 광다이오드를 제작하고 그 특성을 조사하였다. a-SiN : H와 p-a-Si : H막의 차단층이 없는 ITO/a-Si : H/Al 광다이오드의 광감도는 5 V의 인가전압에서 0.7로 나타났으며 가시광영역에서의 분광감도는 620 nm의 파장에서 가장 높게 나타났다. ITO/a-SiN : H/a-Si : H/p-a-Si : H/Al 광다이오드의 암전류는 정공차단막과 전자차단막의 작용으로 인하여 10V의 인가전압까지 1.5pA이하로 억제되었다. 또한 광감도는 3 V의 인가전압에서 약 1로 가장 높게 나타났으며 분광감도는 540 nm의 파장에서 최대응답을 보였다.

• 한국재료학회지
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• 제32권10호
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• pp.403-407
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• 2022

This research investigated the effect of Si addition on the microstructure, mechanical properties, electric and thermal conductivity of as-extruded Al 6013 alloys. As the content of Si increased, the area fraction of the second phase increased. As the Si content increased, the average grain size decreased remarkably, from 182 (no Si addition) to 142 (1.5Si), 78 (3.0Si) and 77 ㎛ (4.5Si) due to dynamic recrystallization by the dispersed second particles in the aluminum matrix during the hot extrusion. As the Si content increased, the yield strength and ultimate tensile strength increased. The maximum values of yield strength and ultimate tensile strength were 224 MPa and 103 MPa for the 6013-4.5Si alloy. As the amount of Si added increased, the electrical and thermal conductivity decreased. The electrical and thermal conductivity of the Al6013-4.5Si alloy were 44.0 % IACS and 165.0 W/mK, respectively. The addition of Si to Al 6013 alloy had a significant effect on its thermal conductivity and mechanical properties.

• 한국재료학회지
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• 제7권10호
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• pp.845-850
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• 1997

수직형 FHD증착법을 사용하여 SiO$_{2}$, SiO$_{2}$-P$_{2}$O$_{5}$, SiO$_{2}$P$_{2}$O$_{5}$-B$_{2}$O$_{3}$-GeO$_{2}$계 실리카 유리미립자를 형성하였으며, SEM, ICP-AES, XRD, TGA-DSC을 사용하여 그 특성을 분석하였다. XRD측정을 통해, 미립자 형성시 사용된 화염온도(130$0^{\circ}C$-150$0^{\circ}C$)와 기판온도(-20$0^{\circ}C$)가 SiO$_{2}$-P$_{2}$O$_{5}$계 미립자를 비정질상태로 형성하였으며, SiO$_{2}$P$_{2}$O$_{5}$-B$_{2}$O$_{3}$와 SiO$_{2}$P$_{2}$O$_{5}$-B$_{2}$O$_{3}$-GeO$_{2}$계 미립자에서는 B$_{2}$O$_{3}$, BPO$_{4}$, GeO$_{2}$의 결정성피크들을 관찰하였다. TGA-DSC 열분석을 통해, SiO$_{2}$와 SiO$_{2}$-P$_{2}$O$_{5}$는 온도변화에 따른 질량변화가 없었으며, SiO$_{2}$P$_{2}$O$_{5}$-B$_{2}$O$_{3}$-GeO$_{2}$계의 경우 질량감소를 동반한 유리전이에 따른 분자이완현상 및 결정화나 회복반응을 나타내고 있다. 질량감소는 미립자가 결정상태일때 가속되는 경향을 나타냈으며, DSC열분석을 통해 SiO$_{2}$, SiO$_{2}$-P$_{2}$O$_{5}$, SiO$_{2}$P$_{2}$O$_{5}$-B$_{2}$O$_{3}$-GeO$_{2}$계 유리미립자들의 고밀화가 시작되는 온도를 각각 1224$^{\circ}C$, 1151$^{\circ}C$, 953$^{\circ}C$, 113$0^{\circ}C$에서 관찰하였다.

• 전기화학회지
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• 제9권1호
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• pp.34-39
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• 2006

Li free 음극으로써 구리 foil 집전체에 $Li_{0.5}La_{0.5}TiO_3$ 및 Si 박막을 r.f, 스퍼터링법을 이용하여 증착하고 양극 물질로는 $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$를 이용하여 전기화학적 특성을 평가하였다. 박막 증착시 플라즈마 내(in-plasma)와 밖(out of plasma)에 구리 foil을 각각 위치시켰다. X-ray 회절 분석의 경우 각각의 조건에서 $Li_{0.5}La_{0.5}TiO_3$ 및 Si 모두 결정 특성의 차이를 발견할 수 없었다. $Li_{0.5}La_{0.5}TiO_3$의 경우 플라즈마 내에서 증착된 경우 그리고 Si 경우는 플라즈마 밖에서 증착된 경우 각각 싸이클 특성이 우수한 것으로 나타났다. 이는 $Li_{0.5}La_{0.5}TiO_3$ 경우 결정성이 존재할 경우 이온전도 특성이 우수하며 Si 경우 플라즈마 내에서 성장된 박막이 더욱 치밀하여 충방전 중 부피변화에 더욱 민감하였기 때문으로 판단된다. 이상의 결과로부터 (1)전지 용량을 갖는 5게 의한 표면 개질의 경우 구조적으로 안정할 수 있는 비정질 상의 Si이 보다 더 바람직하며 (2) 이온전도 특성을 보이는 $Li_{0.5}La_{0.5}TiO_3$와 같은 소재를 이용하여 표면 개질을 할 경우 Li의 확산이 더욱 용이한 구조가 바람직할 것으로 판단된다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권2호
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• pp.136-147
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• 2005

A theoretical design evaluation based on a hydrodynamic transport simulation of strained Si-SiGe on insulator (SSOI) type nMOSFETs is reported. Although, the net performance improvement is quite limited by the short channel effects, simulation results clearly show that the strained Si-SiGe type nMOSFETs are well-suited for gate lengths down to 20 nm. Simulation results show that the improvement in the transconductance with decreasing gate length is limited by the long-range Coulomb scattering. An influence of lateral and vertical diffusion of shallow dopants in the source/drain extension regions on the device performance (i.e., threshold voltage shift, subthreshold slope, current drivability and transconductance) is quantitatively assessed. An optimum layer thickness ($t_{si}$ of 5 and $t_{sg}$ of 10 nm) with shallow Junction depth (5-10 nm) and controlled lateral diffusion with steep doping gradient is needed to realize the sub-50 nm gate strained Si-SiGe type nMOSFETs.

• 한국주조공학회지
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• 제10권3호
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• pp.225-234
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• 1990

Spheroidal graphite cast irons which are Fe-3%C-(4－6)%Si-(0－0.5)%Mo were studied to improve not only heat resistance but also mechanical properties. With increasing Mo content, the graphitization was decreased and carbide volume fraction was increased. The graphite spheroidization ratio was not decreased in Fe-3%C-6%Si-Mo system cast iron with increasing Mo content, but that was decreased in Fe-3%C-4%Si-Mo system and Fe-3%C-5%Si-Mo system cast irons. Hardness was increased with the Si and Mo contents. At constant Si content, tensile strength was increased with increasing Mo content, but that was decreased at 6%Si. In the experiment of oxidation, weight gain was decreased as the Si and/or Mo content increased, but increased at 1.5%Mo content.

• 한국표면공학회지
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• 제49권5호
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• pp.467-471
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• 2016

In order to investigate the Na gettering, PSG/$SiO_2$/Al-1%Si multilevel thin films were fabricated. DC magnetron sputter techniques and APCVD (atmosphere pressure chemical vapor deposition) were utilized for the deposition of Al-1%Si thin films and PSG/$SiO_2$ passivations, respectively. Heat treatment was carried out at $300^{\circ}C$ for 5 h in air. SIMS (secondary ion mass spectrometry) depth profiling and XPS (X-ray Photoelectron Spectroscopy) analysis were used to determine the distribution and binding energies of Na, Al, Si, O, P and other elements throughout the PSG/$SiO_2$/Al-1%Si multilevel thin films. Na peaks were mainly observed at the the PSG/$SiO_2$ interface and at the $SiO_2$/Al-1%Si interfaces. Na impurity gettering in PSG/$SiO_2$/Al-1%Si multilevel thin films is considered to be caused by a segregation type of gettering. The chemical state of Si and O elements in PSG passivation appears to be $SiO_2$.