• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.115-116
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• 2005

Si nanowires (NWs) were fabricated in vacuum furnace by using a Nd:YAG pulsed laser with the wavelength of 325 nm. Commercial p-type Si wafer is used for target, and any catalytic materials are not used. Scanning electron microscopy (SEM) images indicate that the diameters of Si NWs ranged from 10 to 150 nm. Si NWs have various size and shape with a substrate position inside a furnace, and their morphologic construction is reproducible. The formation mechanism of the NWs is discussed.

• Progress in Superconductivity
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• v.13 no.2
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• pp.117-121
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• 2011

We have fabricated $FeSe_x$ superconducting thin films at much different substrate temperatures of 430 and $610^{\circ}C$ on $Al_2O_3$(0001) substrates by using a pulsed laser deposition (PLD) technique. Superconducting transitions for both films were shown around 10 K, but their transition width and growth directions of grains were different. We found that superconducting tetragonal FeSe phases and non-superconducting hexagonal FeSe phases were coexisted in the sample grown at the low temperature of $430^{\circ}C$, whereas the hexagonal FeSe phase was decreased with increasing fabrication temperatures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.391-391
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• 2010

The stability enhancement of Znic oxide thin film transistor deposited by PLD-DBD has been reported here using the bias temperature stress test. Znic oxide (ZnO) thin films were deposited on $SiO_2$/Si (100) by pulsed laser deposition method with and without dielectric barrier discharge (DBD) method. The DBD is the efficient method to adopt the nitrogen ions into the thin films. The TFT characteristics of ZnO TFTs with and without Nirogen (N) doping show similar results with $I_{on/off}$ of $10^5{\sim}10^6$. However. the bias temperature stress (BTS) test of N-doped ZnO TFT with DBD shows higher stability than that of ZnO TFT.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.101-102
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• 2009

We described the growth of undoped ZnO thin films and their optical properties changing with a various growth temperature. The un doped ZnO thin films were grown on c-$Al_2O_3$ substrates using pulsed laser deposition (PLD) at room temperature, 200, 400, and $600^{\circ}C$, respectively. Field emission microscopy (FE-SEM) measurements showed that the grain size of undoped ZnO thin films are increasing as a increase of growth temperature. In addition, we were investigated that the structural and optical properties of undoped ZnO thin films by x-ray diffraction (XRD) and photoluminescence (PL) studied. Also, we could confirmed that the exciton luminescence was strongly related to charge trap by grain boundary of the samples using micro-PL measurement.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.379-379
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• 2012

본 연구에서는 고품질의 ZnO 박막을 제작하기 위해 사파이어 기판 위에 ZnO 박막을 Pulsed Laser Deposition (PLD) 법으로 성장하였다. 레이저 에너지 밀도와 펄스주파수를 고정시켰으며, 성장온도와 산소 분압은 각각 $450{\sim}600^{\circ}C$ 및 5~20 sccm으로 변화를 주어 성장 온도와 산소 분압이 박막 특성에 미치는 영향을 분석하였다. 제작된 박막의 전기적 특성을 측정한 결과 성장온도의 증가에 따라 캐리어 농도는 $9.18{\times}10^{18}cm^{-3}$에서 $3.9{\times}10^{16}cm^{-3}$까지 감소하였고, 캐리어 이동도는 $0.95cm^2/Vs$에서 $8.47cm^2/Vs$ 까지 증가하는 경향을 나타내었으며, 산소분압의 변화에는 특정 임계조건을 갖는 것을 확인하였다. 이러한 이유는 PLD 법 성장 메커니즘에서 플라즈마 플럼(plasma flume) 내에 결합된 ZnO 분자가 기판으로 직접 성장이 이루어지는 과정에서 성장 온도가 증가함에 따라 플럼 내에서 결합 된 ZnO 분자의 열적 안정성이 향상되었으며, 유입되는 산소량의 감소로 인해 원자들의 표면 확산 거리 및 확산 시간이 길어져 보다 안정적인 박막 형성에 기인한 것으로 보인다.

• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.252-257
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• 2004

$Y_{2}O_{3}:Eu^{3+}$ thin films have been grown on $Al_{2}O_{3}$(0001) substrates by a pulsed laser deposition (PLD) method. The phosphor thin films were deposited at a substrate temperature of 500, 600, and $700^{\circ}C$ under the oxygen pressure of 100, 200, and 300 mTorr. The crystallinity, surface roughness and photoluminescence of the films are highly dependent on the substrate temperature and oxygen pressure. The films grown on $Al_{2}O_{3}$(0001) substrate even under the different substrate temperatures and oxygen pressures exhibited (222) preferred orientation. The luminescent spectra exhibited strong luminescence of ${^{5}D_{0}}-{^{7}F_{2}}$ transition within $Eu^{+3}$ peaking at 612 nm. The crystallinity and luminescence intensity of the films have been improved as the substrate temperature increasing. With increase of oxygen pressure from 50 to 300 mTorr, the crystallinity of the films has been uniformly decreased. The photoluminescence intensity and surface roughness have similar behaviors as a function of oxygen pressure. At 200 mTorr, both photoluminescence intensity and surface roughness show a maximum.

• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.593-598
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• 2004

To make the all-solid-state lithium thin film battery having less than 1 fm in thickness, LiCoO$_2$ thin films were deposited on Pt/TiO$_2$/SiO$_2$/Si substrate as a function of Li/Co mole ratio and the deposition temperature by Pulsed Laser Deposition (PLD). Especially, LiCoO$_2$ thin films deposited at 50$0^{\circ}C$ with target of Li/Co=1.2 mole ratio show an initial discharge capacity of 53 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 67.6％. The microstructural and electrochemical properies of (Li, La)TiO3 thin films grown on LiCoO$_2$Pt/TiO$_2$/SiO$_2$/Si structures by Pulsed Laser Deposition (PLD) were investigated at various deposition temperatures. The thin films grown at 10$0^{\circ}C$ show an initial discharge capacity of approximately 51 $\mu$Ah/cm$^2$-$\mu$m and moreover show excellent discharge capacity retention of 90％ after 100 cycles. An amorphous (Li, La)TiO$_3$ solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium thin film battery below 1 $\mu$m.

• Progress in Superconductivity
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• v.5 no.1
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• pp.75-79
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• 2003

YBCO films were deposited with various thicknesses from 100nm to 1.6$\mu\textrm{m}$ on single crystal $SrTiO_3$ substrates by pulsed laser deposition (PLD). The effects of different deposition conditions, especially different deposition rates by means of changing the pulsed laser frequency up to 200Hz, on the J$_{c}$ value were studied. For YBCO film with the thickness of 200nm, the $J_{c}$ value of $2.1MA/\textrm{cm}^2$ has been achieved under the high deposition rate of 3.2nm/s (190nm/min). The $J_{c}$ can be maintained greater than $1M/\textrm{cm}^2$ with the thickness less than 1$\mu\textrm{m}$. The X-ray analysis was used to examine the texture, crystallization and surface quality. The SEM was employed to analyze the surface of YBCO, and it was shown the surface of YBCO film became rougher with increasing the thickness. There were many large singular outgrowths and networks of outgrowths on the surface of YBCO films which lowered the density of thick YBCO film. The outgrowth network was probably the a-axis YBCO corresponding to XRD $\theta$-2$\theta$scan and $\chi$-scan which were used to characterize a-axis orientation of YBCO film. The reason for J$_{c}$ declining with increasing the thickness was studied and discussed.sed.

• ETRI Journal
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• v.27 no.4
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• pp.405-410
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• 2005

High quality indium tin oxide (ITO) thin films were grown by pulse laser deposition (PLD) on flexible polyethersulphone (PES) substrates. The electrical, optical, and surface morphological properties of these films were examined as a function of substrate temperature and oxygen pressure. ITO thin films, deposited by PLD on a PES substrate at room temperature and an oxygen pressure of 15 mTorr, have a low electrical resistivity of $2.9{\times}10^{-4}{\Omega}cm$ and a high optical transmittance of 84 % in the visible range. They were used as the anode in organic light-emitting diodes (OLEDs). The maximum electro luminescence (EL) and current density at 100 $cd/m^2$ were 2500 $cd/m^{2}$ and 2 $mA/m^{2}$, respectively, and the external quantum efficiency of the OLEDs was found to be 2.0 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.126-129
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• 2001

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.