• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.25-28
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• 2012

Tin-oxide ($SnO_2$) nanowires have been synthesized on one-dimensional (1D) carbonization cotton fabric using chemical vapour deposition method. One-dimensional (1D) carbonization cotton fabric has been synthesized from cotton fabric using annealing process in nitrogen gas at $1000^{\circ}C$. The $SnO_2$ nanowires are single-crystalline rutile structures with 20 nm in diameter and 10 ${\mu}m$ in length. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy and photoluminescence (PL) spectroscopy were utilized to characterize the as-synthesized products.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.848-854
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• 2012

SCM420 steel cutting gear to improve the durability is quenched. When quenching, increases surface hardness, a change of the physical properties and machinability or fall. This study, using a solid carbide hobs skiving hobbing gear cutting finishing. And cutting tool solid carbide TiAlN coating hove when TiAlN coating on the surface of multi-con polishing hob conducted aero lap nano polishing for each cutting. Experimental results conducted aero lap nano coating on the surface polishing tool machinability was excellent. And aero lap nano polishing tool results were reduced 2.5 times the tool wear compared to TiAlN coated tools. Excellent results were 1.42 times longer tool life.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.486-492
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• 1998

Silicon carbide (SiC) thin films were deposited on the porous silicon substrates by chemical vapour de-position(CVD) using MTS as a source material. The deposited films were ${\beta}$-SiC with poor crystallity con-firmed by XRD measurement. It was considered that the films showed the mixed characteistics of cry-stalline and amorphous SiC where amorphous SiC where amorphous SiC played a role of buffer layer in interface between as-dep films and Si substrate. The buffer layer reduced lattice mismatch to some extent the generally occurs when SiC films are deposited on Si. The low temperature (10K) PL (phtoluminescence) studies showed two broad bands with peaks at 600 and 720 for the films deposited at 1100$^{\circ}C$ The maximum PL peak of the crystalline SiC was observed at 600 nm and the amrophous SiC of 720 nm was also confirmed. PL peak due the amorphous SiC was smaller than that of the crystalline SiC, PL of porous Si might be disapperared due to densification during heat treatment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1402-1408
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• 1990

We studied the electrical, optical and structural properties of microcrystalline silicon thin films prepared by a new chemical vapour deposition technique, called filament assisted(FA)-CVD. The microcrystalline silicon is sucessfully deposited when the hydrogen dilution ratio exceeds 30. The Raman peak at 520 cm-1 and the X-ray diffraction peak at 27.7\ulcorner0.2\ulcornerbecome sharper with increasing hydrogen dilution ratio. We obtain high quality microcrystalline Si by FA-CVD with optical gap of \ulcorner2.2eV and hydrogen content of \ulcorner3 at %.

• Carbon letters
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• v.6 no.2
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• pp.79-85
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• 2005

The work reported in this paper relates to preparation and characterization of carbon nanomaterials by CVD method on different substrates by decomposition of certain hydrocarbons at 550-$800^{\circ}C$ using a horizontal quartz tube reactor. Monometallic and bimetallic catalyst system of iron and nickel were used for the preparation of different carbon nanomaterials. The influence of various parameters such as substrate/catalyst preparation parameters, the nature of substrate, catalyst concentration, reaction time and temperature on the growth, yield and alignment of carbon nanotubes has been studied. The characterization of carbon nanomaterials has been carried out using SEM, TEM and TGA. The carbon nanomaterials developed were vertically aligned on a large area of flat quartz substrate.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.1008-1012
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• 1996

I-V, C-V characteristics of inverted staggered type hydrogenerated amorphous silicon thin film transistor(a-Si:H TFT) was studied and experimentally verified. The results show that the log-log plot of drain current increased by voltage increase. The saturated drain current of DC output characteristics increased at a fixed gate voltage. According to the increase of gate voltage, activation energy of electron and the increasing width of Id at high voltage were decreased. Id saturation current saturated at high Vd over 4.5V, Vg-ld hysteresis characteristic curves occurred between -15V and 15V of Vg. Hysteresis current decreased at low voltage of -15V and increased at high voltage of 15V.

• Korean Journal of Crystallography
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• v.9 no.2
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• pp.131-137
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• 1998

결정결함의 밀도가 낮은 GaN epitaxy 막을 MOCVD(metal organic chemical vapour deposition) 방법에 의해 성장시켰다. 기판은 6H-SiC를 사용하였으며, AlN과 GaN으로 구성된 이중 buffer 층을 도입하였다. GaN buffer 층은 반응원료인 trimethyl gallium(TMG)과 NH3 가스를 교호식펄스공급(alternating pulsative supply, APS)방법에 의해 만들었다. AlN buffer/6H-SiC 위에 초기단계에 형성되는 GaN 섬은 APS처리에 의해 크기가 커지는 것을 AFM(atomic force microscope)으로 관찰하였다. Buffer 층의 역할은 그 위에 성막시킨 GaN epitaxy 막의 결정성과 결함밀도에 의해 조사하였다. 성막된 GaN의 결정구조와 결정성은 DCXRD(double crystal X-ray diffractormeter)에 의해 측정되었다. 결정결함은 EPD(etching pit density)를 측정하는 방법으로 알칼리혼합용에서 처리된 막을 SEM(scanning electron microscope)으로 관찰하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.5
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• pp.350-355
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• 2000

The fabrication of sapphire wafer in C plane has been developed by horizontal Bridgeman method and GaN based semiconductor epitaxial growth has been carried out in metal organic chemical vapour deposition. The single crystalline ingot of sapphire has been utilized for 2 inch sapphire wafers and wafer slicing and lapping machines were designed. These several steps of lapping processes provided the mirror-like surface of sapphire wafer. The measurements of the surface flatness and the roughness were carried out by the atomic force microscope. The GaN thin film growth on the developed wafer was confirmed the wafer quality and applicability to blue light emitting devices.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.602-603
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• 2006

Micro-porous nickel (Ni) with an open cell structure was fabricated by powder metallurgy. The pore size of the micro-porous Ni approximated $30{\mu}m$ and $150{\mu}m$. For comparison, porous Ni with a macro-porous structure were also prepared by both powder metallurgy (pore size $800{\mu}m$) and the traditional chemical vapour deposition method (pore size $1300{\mu}m$). The mechanical properties of the micro-and macro-porous Ni samples were evaluated using compressive tests. Results indicate that the micro-porous Ni samples exhibited significantly enhanced mechanical properties, compared to those of the macro-porous Ni samples.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.614-619
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• 2005

The activated carbon fibers of different surface area and pore structures were modified by carbon deposition from the pyrolysis of benzene, in an attempt to obtain carbon molecular sieves of high adsorption capacity and selectivity for the separation of $CO_2/CH_4$ gas mixtures. The ACFs molecular sieves prepared from different temperature and time were tested by the static adsorption of $CO_2$ and $CH_4$ gas, and their pore structures were characterized by the $N_2$ adsorption isotherms. We are able to prepare ACF molecular sieve with good selectivity for $CO_2/CH_4$ separation and showing acceptable adsorption capacities from the change of porosity by carbon deposition of pyrolyzed benzene.