• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.250-250
• /
• 2011

Zinc oxide (ZnO) structures have great potential in many applications. Currently, the most commonly used method to grow ZnO nanostructres are the vapor transport method (VPT). The morphology of the ZnO structures largely related to the growth conditions, including growth temperature, distance between the substrate and source, and gas ambient. Previously ZnO nanosturecutres with high crystallinity were obtained at the growth temperature of 800$^{\circ}C$, in the argon and oxygen gas ambient. In this study, we report the properties of the ZnO nanostructures, which were synthesized on Au-catalyzed Si substrate by VPT, using a mixture of ZnO and graphite powders as source material under the different condition, including gas ratio of argon/oxygen and distance between substrate and source at the growth temperature of 800$^{\circ}C$. The structural and optical properties of the ZnO nanostructures were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL).

• 한국전기전자재료학회논문지
• /
• 제13권2호
• /
• pp.95-100
• /
• 2000

For the well-controlled growing in-situ heavily phosphorus doped polycrystalline Si films directly on Si wafer by reduced pressure chemical vapor deposition, a study is made of the two step growth. When in-situ heavily phosphorus doped Si films were deposited directly on Si (100) wafer, crystal structure in the film is not unique, that is, the single crystal to polycrystalline phase transition occurs at a certain thickness. However, the well-controlled polycrtstalline Si films deposited by two step growth grew directly on Si wafers. Moreover, the two step growth, which employs crystallization of grew directly on Si wafers. Moreover, the two step growth which employs crystallization of amorphous silicon layer grown at low temperature, reveals crucial advantages in manipulating polycrystal structures of in-situ phosphorous doped silicon.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.123-126
• /
• 2001

Multiwalled carbon nanotubes were massively produced by the catalytic reaction of C$_2$H$_2$ - Fe(CO)$\sub$5/ mixture at 750 - 950$^{\circ}C$ in a quartz tube reactor and over quartz substrates. Well-aligned MWNT array grows perpendicular to the quartz tube reactor and the quartz substrates at an average of 60 nm in diameter and up to several thousands of micrometers in length. This method does not require any pretreatment of substrates and CNTs are grown at atmospheric pressure. It could be suitable for mass production of multiwalled nanotubes. Scanning electron microscope and transmission electron microscope images of the nanotubes deposited on the substrates allowed us to monitor the quality of MWNTs grown under different operating conditions.

• 한국세라믹학회지
• /
• 제43권6호
• /
• pp.376-382
• /
• 2006

In the $Al(OH)_3-SiO_2-AlF_3$ system, leaf-shaped fluorotopaz was first formed at $800^{\circ}C$ and mullite whisker was formed at $1,100^{\circ}C$. The mass transportation of Al and Si as gas phase, the fast reaction and growth, and the absence of liquid phase existence in mullite whisker showed that the formation and growth of mullite was from the solid-vapor reaction.

• 한국결정학회지
• /
• 제8권2호
• /
• pp.81-88
• /
• 1997

GaN와 $NH_3$를 source gas로 사용하여 (0001) sapphire 기판에 CVPE(Chloride Vapor Epitaxy)방법으로 GaN 박막을 성장시킨후 그 특성을 조사하였다. 성장온도 $970^{\circ}C$ 부터 $1040^{\circ}C$ 영역에서 source gas의 유량비를 변화하면서 최적증착조건을 구현하였고, GaN증착이전에 $NH_3$ 가스로써 질화전처리를 하였다. 수행된 실험조건범위내에서 최적증착조건은 증착온도 $1040^{\circ}C$에서 질화전 처리 3분으로 III/V source gas의 유량비율이 2일 때 였으며, 이때의 XRD분석에서의 FWHM값은(0001) peak에서 약 0.32deg를 나타내었다. GaN박막성장속도는 이때 약 $1040^{\circ}C$였다.

• 한국결정성장학회지
• /
• 제20권3호
• /
• pp.117-124
• /
• 2010

For Ar=5, Pr=1.18, Le=0.15, Pe=2.89, Cv=1.06, $P_B$=20 Torr, the effects of impurity $(N_2)$ on thermally and solutally buoyancy-driven convection ($Gr_t=3.46{\times}10^4$ and $Gr_s=6.02{\times}10^5$, respectively) are theoretically investigated for further understanding and insight into an essence of thermo-solutal convection occurring in the vapor phase during the physical vapor transport. For $10K{\leq}{\Delta}T{\leq}50K$, the crystal growth rates are intimately related and linearly proportional to a temperature difference between the source and crystal region which is a driving force for thermally buoyancy-driven convection. Moreover, both the dimensionless Peclet number (Pe) and dimensional maximum velocity magnitudes are directly and linearly proportional to ${\Delta}T$. The growth rate is second order-exponentially decayed for $2{\leq}Ar{\leq}5$. This is related to a finding that the effects of side walls tend to stabilize the thermo-solutal convection in the growth reactor. Finally, the growth rate is found to be first order exponentially decayed for $10{\leq}P_B{\leq}200$ Torr.

• 한국결정성장학회지
• /
• 제24권2호
• /
• pp.54-58
• /
• 2014

PVT(물리 기상 이동법, Physical Vapor Transport) 법을 적용하여 질화알루미늄(AlN, Aluminum Nitride) 단결정을 성장하였으며, 성장된 결정의 결정성과 성장 온도에 따른 상에 대하여 고찰하였다. 성장된 단결정은 광학현미경을 이용하여 결정의 상을 관찰하였고, 관찰된 결과를 비교 분석하여 본 실험에 적용된 성장 장치에서의 최적의 성장 온도 조건을 설정할 수 있었다. 본 연구에서는 AlN 단결정 성장 결과를 비교 고찰하여 보고하고자 한다.

• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 15TH KACG TECHNICAL MEETING-PACIFIC RIM 3 SATELLITE SYMPOSIUM SESSION 4, HOTEL HYUNDAI, KYONGJU, SEPTEMBER 20-23, 1998
• /
• pp.1-20
• /
• 1998

Processing of thin films by chemical vapor deposition (CVD) is accompanied by chemical reactions, in which the rigorous kinetic analysis is difficult to achieve. In these conditions, thermodynamic calculation leads to better understanding of the CVD process and helps to optimise the experimental parameters to obtain a desired product. A CVD phase diagram has been used as guide lines for the process. By determining the effect of each process variable on the driving force for deposition, the thermodynamic limit for the substrate temperature that diamond can deposit is calculated in the C-H system by assuming that the limit is defined by the CVD diamond phase diagram. The addition of iso-supersaturation ratio lines to the CVD phase diagram in the Si-Cl-H system provides additional information about the effects of CVD process variables.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1996년도 제11회 학술발표회 논문개요집
• /
• pp.28-28
• /
• 1996

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1995년도 추계 학술발표 강연 및 논문개요집
• /
• pp.14-14
• /
• 1995