• 한국결정성장학회지
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• 제9권2호
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• pp.137-140
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• 1999

Flux법에 의해 성장된 $Bi_2Sr_2CaCu_2O_{8+{\delta}}(Bi2212)$ 단결정의 초전도 특성에 미치는 열처리 및 불순물의 영향을 자화측정에 의해 조사하였다. 초전도 특성은 불순물인 Mg와 Al의 영향을 받음을 알 수 있었으며, 초전도 전이온도(T,) 는 Mg 불순물의 영향에 의해 보다 낮아졌다. 그러나 성장된 결정은 열처리에 의해 초전도 특성이 개선됨을 알 수 있었 으며, 특히 MgO 도가니 사용에 의해 성장된 결정이 $Al_2O_3$ 도가니에 비해서 반자계특성이 현저하게 증가되었다. 반자계 특성의 개선효과에 의해 Mg 불순물은 초전도 특성 열화의 주요 요소라고 생각될 수 없음을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제13권10호
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• pp.828-833
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• 2000

Growth characteristics and microstructure of AIN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the micorstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.462-466
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• 2012

In this paper, heat-releasing composite sheets made of AlN, graphite, Al powder and acryl binder as thermoset were prepared using tape casting method. The crystal structure, morphology, thermal conductivity of heat-releasing composite sheet were measured by using X-ray diffractometer, field emission-scanning electron microscopy and laser flash instrument. It was found thermal conductivity of sheet was decided by solid content, composition including AlN, graphite, Al in heat-releasing composite sheets. As a result, 4.56 W/mK of thermal conductivity could be obtained by using LFA 447.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.431-434
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• 2012

In this paper, heat-releasing sheets made of AlN powder and acryl binder as thermoset were prepared using tape casting method. The crystal structure and morphology, the thermal properties as nonvolatile solid content and thermal conductivity, and the surface resistance of heat-releasing sheet were measured by using X-ray diffractometer, field emission-scanning electron microscopy, thermo gravimetric analyzer and laser flash instrument, and surface resistance meter. It was proved that thermal conductivity is greatly affected by the content of binder in heat-releasing sheet. Superior thermal conductivity above 3.5 W/mK and suface resistance were obtained at heat-releasing sheet with above 90% of AlN powder.

• 센서학회지
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• 제13권2호
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• pp.157-167
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• 2004

A stoichiometric mixture of evaporating materials for $CuAlSe_{2}$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_{2}$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_{2}$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}cm^{-3}$ and $295cm^{2}/V{\codt}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$ = 2.8382 eV - ($8.68{\circ}10^{-4}$ eV/K)$T^{2}$/(T + 155 K). The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_{2}$ have been estimated to be 0.2026 eV and 0.2165 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_{5}$ states of the valence band of the $CuAlSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1-}$, $B_{1-}$, and $C_{1-}$ exciton peaks for n = 1.

• Bulletin of the Korean Chemical Society
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• 제20권1호
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• pp.65-68
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• 1999

Novel mononuclear group 13 metal complexes with the formula (R2M){NC5H4C(CH3)NNC(S)NH(C6H5)} (M=Al, R=iC4H9 (1); M=Ga, R=iC4H9 (2); M=Al, R=CH2SiMe3 (3); M=Ga, R=CH2SiMe3 (4)) result when 2-acetyl pyridine 4-phenyl-thiosemicarbazone ligand is mixed with trialkyl aluminum or trialkylgallium. These compounds 1-4 are characterized by microanalysis, NMR (1H, 13C) spectroscopy, mass spectra, and singlecrystal X-ray diffraction. X-ray single-crystal diffraction analysis reveals that 1 is mononuclear metal compound with coordination number of 5 and N, N, S-coordination mode.

• 센서학회지
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• 제23권6호
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• pp.420-424
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• 2014

Aluminum-scandium nitride ($Al_{1-x}Sc_xN$) thin films with a TiN buffer layer have been fabricated on SUS430 substrate by RF reactive magnetron sputtering at room temperature under 50% $N_2$/Ar. The effect of Sc-doping on the structure and piezoelectric properties of AlN films has been investigated using SEM, XRD, surface profiler and pressure-voltage measurements. The as-deposited AlN films showed polycrystalline phase, and the Sc-doped AlN film, the peak of AlN (002) plane and the crystallinity became very strong. With Sc-doping, the crystal size of AlN film was grown from ~20 nm to ~100 nm. The output signal voltage of AlN sensor showed a linear behavior between 15~65 mV, and output signal voltage of Sc-doped AlN sensor was increased over 7 times. The pressure-sensing sensitivity of AlN film was calculated about 10.6mV/MPa, and $Al_{0.88}Sc_{0.12}N$ film was calculated about 76 mV/MPa.

• 한국결정성장학회지
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• 제30권3호
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• pp.83-90
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• 2020

열전도성이 우수한 AlN 기판에 형성되는 Ag계 후막도체의 접착강도에 미치는 기판 표면조도 및 소결 온도의 영향을 연구하였다. 표면조도(R_a)가 0.5인 AlN 기판을 사용하여 제조한 후막도체의 접착강도가 이보다 표면조도가 크거나 또는 작은 기판을 사용하여 제조한 후막도체의 경우보다 높게 나타났다. 표면조도가 0.5보다 작은 기판의 경우 Ag 후막도체와 기판 사이의 접촉면적이 표면조도가 0.5인 기판보다 상대적으로 작아 접착강도가 작게 나타났다. 한편, 표면조도가 0.5보다 큰 기판을 사용한 경우에는 도체막이 기판에 완전히 접착되지 못하는 현상이 나타났고, 이로 인해서 접착강도가 적게 나타남을 알 수 있었다. 또한, 850℃에서 소결하여 얻어진 Ag계 후막도체 막의 표면 평활도가 다른 소결 온도에서 소결하여 얻어진 도체막의 평활도에 비해 가장 우수하였고, 이로 인해 도체막의 접착강도가 가장 높게 나타남을 알 수 있었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.47-47
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• 2008

Cr and AlSi (Si=20 and 66 at.%) target들을 이용하여 Closed-field unbalanced magnetron sputtering (CFUBMS)으로 증착된 주기($\Lambda$)가 2.3 nm에서 8.0nm인 CrN/AlSiN multilayer coatings의 crystal structure, 화학적 조성, 및 기계적 특성을 glow discharge optical emission spectroscopy (GDOES), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and nano-indenter 등의 분석장비를 이용하여 분석하였다. 고온안정성을 시험하기 위하여 $800^{\circ}C$와 $1000^{\circ}C$ 공기중 에서 30분 열처리하였다. CrN/AlSiN multilayer coatings의 고온안정성은 Si조성이 증가함에 따라 향상되었다. Si이 18.2 at.%함유된 coating이 가장 우수한 고온안정성을 갖고 있다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.97.2-97.2
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• 2018

This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed and refined. The TiAlSi and TiAlSiW coating targets were fabricated using a single PCAS process in a short time with the optimal sintering conditions. The coating targets were deposited on the WC substrate by forming coating layers using TiAlSiN and TiAlSiWN nitride nano-composite structures with an AIP process. The properties of the nitride nano-composite coating layers were compared according to the addition of W. The microstructure of the nitride nano-composite coating layer was analyzed, focusing on the distribution of the crystalline phases, amorphous phases ($Si_3N_4$), and growth orientation of the columnar crystal depending on the addition of W. The mechanical properties of the coating layers were exhibited a hardness of approximately $3,000kg/mm^2$ and adhesion of about 117.77N in the TiAlSiN. In particular, the TiAlSiWN showed excellent properties with a hardness of more than $4,300kg/mm^2$ and an adhesion of about 181.47N.