• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.541-545
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• 1998

(PZT, PST, PT)/ YBCO structured have been grown on single crystal $LaAlO_3$ using in-situ Nb:YAG pulsed laser deposition technique. The optimum conditions of fabrication for high quality films have been established under various oxygen pressure. TBCO was used as a metallic electrode for polarizing ferroelectric thin fillms. Lattice mismatch of these materials were found to be with in 3%. As a result XRD patterns and rocking curves, (PZT, PST, PT)/ YBCO multiayered thin films on $LaAlO_3$ substrates showed preferred orientation to c-axis. For invastigation on electrical properties of ferroelectric thin films, remanent polaiztion $P_r$ and coercive field $E_c$ were measured for three samples. At each optimum condition, they showed the values of P_r=60 \mu C/cm^2 and E_c=240kV/ cm for PT, 30\mu C/cm^2 and 105kV/cm for PZT, 1.5\mu C/cm^2$ and 15kV/cm for PST. Frequency dependence of dielectric properties of ferroelectric thin fillms was also investigated. As a result, it showed the frequency dependence was relatively small in the range of 10Hz~10kHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.266-267
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• 2007

$Ba_{0.5}Sr_{0.5}TiO_3$(BST) films with different deposition temperatures were deposited on $Al_2O_3$ substrate by Nd:YAG Pulsed Laser Deposition(PLD). The deposition conditions to achieve high crystal structures and dielectric properties were optimized for both techniques. The structural characterization on the BST thin films was performed by X-Ray Diffraction(XRD) and Atomic Force Microscopy (AFM). Effects of post-deposition annealing of BST films were investigated. The best dielectric properties were obtained on $800^{\circ}C$ deposited BST film with post-deposition annealing at $1100^{\circ}C$ in flowing $O_2$ atmosphere for 2hours.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.292-300
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• 2001

The paper describes spectroscopic characteristics of plasma induces in the pulsed YAG laser welding of alloys containing a large amount of volatile elements. The authors have conducted the spectroscopic analyses of laser induced Al-Mg alloys plasma in the air and argon atmosphere. In the air environment, the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn, and singly ionized Mg lines, as well as the intense molecular spectra of A10 and Mg0 formed by chemical reactions of evaporated Al and Mg atoms from the pool surface with oxygen in the air. In argon atmosphere, Mg0 and AI0 spectra vanished, but AIH spectrum was detected. The hydrogen source was presumably hydrogen dissolved in the base metals, water absorbed on the surface oxide layer, or $H_2$ and $H_2O$ in the shielding gas. The resonant 1ines of Al and Mg were strongly self-absorbed, in particular, self-absorption of the Mg 1ine was predominant. These results show that the laser induced plasma was made of metal1ic vapor with relatively low temperature and high density.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.181-189
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• 2012

We developed a new high-yield synthesis method of free-standing germanium nanocrystals (Ge NCs) by means of the gas-phase photolysis of tetramethyl germanium in a closed reactor using an Nd-YAG pulsed laser. Size control (5-100 nm) can be simply achieved using a quenching gas. The $Ge_{1-x}Si_x$ NCs were synthesized by the photolysis of a tetramethyl silicon gas mixture and their composition was controlled by the partial pressure of precursors. The as-grown NCs are sheathed with thin (1-2 nm) carbon layers, and well dispersed to form a stable colloidal solution. Both Ge NC and Ge-RGO hybrids exhibit excellent cycling performance and high capacity of the lithium ion battery (800 and 1100 mAh/g after 50 cycles, respectively) as promising anode materials for the development of high-performance lithium batteries. This novel synthesis method of Ge NCs is expected to contribute to expand their applications in high-performance energy conversion systems.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2079-2082
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• 2004

This paper study on OLEDs(Organic Light Emitting Diodes) panel using PLD(Pulsed Laser Deposition) methode. Deposition of organic was used Q-stitched Nd/YAG laser in 355 nm and reduced organic pellet for PLD method. Organic morphology was measured AFM(Atomic Forced Microscope) and emitting efficiency was measured luminance meter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.125-128
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• 2000

ZnO thin films on silicon substrates have been deposited by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the effect of oxygen post-annealing treatment on the property of ZnO thin films, deposited film has been annealed at the substrate temperature of $440^{\circ}C$. After post-annealing treatment in the oxygen ambient, the stoichiometry of ZnO film has been characterized be improved which results in higher UV emission intensity of photoluminescence.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.29-32
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• 2001

Hydrogen passivation of Si nanocrystals identifies luminescence mechanism indirectly. Si nanocrystallites thin films on p-type (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser After deposition, Si nanocrystallites thin films have been annealed at 600$^{\circ}C$ and 760$^{\circ}C$ in nitrogen ambient, respectively. Hydrogen passivation was subsequently performed at 500$^{\circ}C$ in forming gas (95 % N$_2$ + 5 % H$_2$) for an 1 hour. We report the photoluminescnece(PL) property of Si thin films by the hydrogen passivation. The luminescence mechanism of Si nanocrystallites has also been investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.38-41
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• 2002

The variation of photoluminescence(PL) properties of Si thin films was investigated by changing deposition temperatures, Si-rich silicon oxide films on p-type (100) Si substrate have been fabricated by pulsed laser deposition(PLD) technique using a Nd:YAG laser. During deposition, the substrates were kept at the temperature range of room temperature(RT) to $400^{\circ}C$. After deposition, samples were annealed at $800^{\circ}C$ in nitrogen ambient, Strong Blue PL has been observed on RT-deposited Si nanocrystallites. When the deposition temperature was increased over $100^{\circ}C$, PL intensities abruptly decreased. The experimental results show the growing mechanism of Si nanocrystallites by PLD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.88-91
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• 2003

Si nanocrystallites thin films have been fabricated by pulsed laser deposition using a Nd:YAG laser. After deposition, samples were annealed at the temperature range of 400 to $800^{\circ}C$. Hydrogen passivation was then performed in the forming gas ($95%N_{2}+5%H_{2}$) at $500^{\circ}C$. Strong violet-indigo photoluminescence has been observed at room temperature on nitrogen ambient-annealed Si nanocrystallites. As a result of photoluminescence spectra and infrared absorption spectra, we conclude that the violet-indigo PL efficiency is related with oxygen vacancy in the $SiO_x$(x= 1.6-1.8) matrix.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2130-2132
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• 1999

This paper is research for the practicability of instrument which can apply to the transformer on the spot with the criteria of insulation oil with the method of measuring the volume of $H_2O$ in the insulation oil by playing insulation oil with the significant role for precaution diagnosis on breakdown of transformer among power system into Nd:YAG laser.