• 한국전기전자재료학회논문지
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• 제17권10호
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• pp.1061-1067
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• 2004

In this study, ferroelectric (Ba,Sr)TiO$_3$ and high temperature superconductor YBCO thin films were fabricated by PLD (Pulsed Laser Deposition) method and tuneable bandstop filters were implemented with two different IDC(Interdigital Capacitance) gap patterns, 20${\mu}{\textrm}{m}$ and 30${\mu}{\textrm}{m}$ using these two thin film layers. The resonant frequency was changed by DC bias voltage. By comparing measured results with simulation, the dielectric properties of ferroelectric thin film have been extracted. The permittivity was 820 ～ 900 at 30 K and had an acceptable error range but the loss tangent had a great difference, 0.018 in 30${\mu}{\textrm}{m}$ IDC gap pattern and 0.037 in 20 ${\mu}{\textrm}{m}$.

• 한국재료학회지
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• 제7권5호
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• pp.431-433
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• 1997

We investigated a double ring resonator(DRR)device to improve the resonating Q value of a superconductor resonator. To make a DRR device, we made a large area YBCO film on a MgO substrate by pulsed laser deposition(PLD). Thetransition temperature was 88 K and the film was uniformly deposited. We also deposited 500$\AA$SrTiO$_{3}$on the YBCO thin film to protect the superconducting properties from degradation. The loaded Q value was measured as 50000 from simulation and as 2000 from experiment near 10GHz at 77K.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.41-43
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• 2004

Dielectric thin films of $(Pb_{0.72}La_{0.28})Ti_{0.93}O_3$ were deposited on $Pt(111)/Ti/SiO_2/Si$ substrates in situ by pulsed laser deposition(PLD) and annealed with different gases which are forming gas and oxygen gas, respectively. The diffusion of hydrogen into the ferroelectric film was caused by annealing process and resulted in the destruction of polarization. The dielectric properties of forming gas annealed PLT thin films, which are dielectric constant, ferroelectric characteristic, and leakage current characteristics, were degraded

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.287-287
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• 2010

휴대용 기기의 사용이 증가하면서 배터리의 고용량화와 소형화가 요구되고 있다. 특히 내시경 캡슐과 같은 의료용 센서 기기에서는 소형화가 매우 중요하며 인체에 해로운 액체전해질이 들어가지 않는 것이 바람직하다. 최근 무선센서, RFID 태그, 스마트 카드 등을 위하여 고체전해질을 사용하는 박막 마이크로 배터리가 개발되고 있으나, 에너지 저장용량이 작아 응용분야가 제한적이다. Si wafer 위에 형성된 고단차의 3차원 구조 위에 박막 배터리를 형성한다면 표면적 증가에 의해 에너지 저장용량 역시 크게 증가할 것이며, Si 기반의 반도체, 디스플레이, 태양전지 등과 쉽게 집적이 가능할 것이다. 본 연구에서는 펄스 레이저 증착법(Pulsed Laser Deposition)으로 리튬 배터리의 cathode 물질인 $LiCoO_2$를 박막으로 제조하고 그 특성을 연구하였다. 펄스 레이저 증착법은 저온 증착이 가능하고 타겟 물질과 같은 조성의 박막을 증착하는 것이 용이한 장점이 있다. Pt, TiN 등의 기판 위에 $LiCoO_2$ 박막을 증착하고 증착 온도와 산소($O_2$) 분압이 박막의 조성, 미세구조, 결정성, 그리고 전하저장용량에 미치는 영향을 고찰하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.169-169
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• 2012

The high-temperature superconductor YBa2Cu3O7-x (YBCO) have attached attentions because of a high superconducting transition temperature, low surface resistance, high superconducting critical current density (Jc), and superior superconducting capability under magnetic field. Moreover, the Jc of YBCO superconductors can be enhanced by adding impurities to the YBCO films for vortex-pinning. Understanding and controlling pinning centers are key factors to realize high Jc superconductors. We synthesized vertically-aligned ZnO nanorods on SrTiO3 (STO) substrates by catalyst-free metal-organic chemical vapor deposition (MOCVD), and subsequently, deposited YBCO films on the ZnO nanorods/STO templates using pulsed laser deposition (PLD). The various techniques were used to analyze the structural and interfacial properties of the YBCO/ZnO nanorods/STO hybrid structures. SEM, TEM, and XRD measurements demonstrated that YBCO films on ZnO nanorods/STO were well crystallized with the (001) orientation. EXAFS measurements from YBCO/ZnO nanorods/STO at Cu K edge demonstrated that the local structural properties around Cu atoms in YBCO were quite similar to those of YBCO/STO.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1270_1271
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• 2009

In this research, gallium-incorporated zinc oxide (ZnO:Ga) thin films have been used as a coating material for enhancing the field-emission property of CNT-emitters. Multi-walled CNTs were directly grown on conical-type ($250{\mu}m$ in diameter) metal-tip substrates at $700^{\circ}C$ by inductively coupled plasma-chemical vapor deposition (ICP-CVD). The pulsed laser deposition (PLD) technique was used to produce 5wt% gallium-doped ZnO (5GZO) films with very low stress. The structural properties of ZnO and 5GZO coated CNTs were characterized by Raman spectroscopy. Field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) were also used to monitor the variation in the morphology and microstructure of CNTs before and after 5GZO-coating. The measurement of the field emission characteristics showed that the emitter that coated the 5GZO (10nm) on CNTs exhibited the best performance: a maximum emission current of $325{\mu}A$, a threshold field of 2.2 V/${\mu}m$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.200-200
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• 2008

This paper reports on electrical characterization by IDC pattern using BST$(Ba_{0.5}Sr_{0.5}TiO_3)$ thin film. BST thin films have been deposited on $Al_2O_3$ Substrates by Nd-YAG pulsed laser deposition with a 355nm wavelength at $700^{\circ}C$. The post deposition annealing at $750^{\circ}C$ in flowing $O_2$ atmosphere for I hours. The capacitance of IDC patterns have been measured from 1 to 10 GHz as a function fo electric field (${\pm}40$ KV/cm) at room temperature using interdiigitated Au electrodes deposited on top of BST. The IDC patterns have three type of fingers number. For the finger paris was increased onto $Al_2O_3$, the capacitance increased. The capacitance of 5 pairs finger was 0.3pF and 10 pairs finger was 0.9pF.

• 한국초전도ㆍ저온공학회논문지
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• 제6권2호
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• pp.7-10
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• 2004

A study regarding the epitaxial growth of single $Y_2O_3$ buffer layer on biaxially textured Ni and NiW substrates using pulsed laser deposition is presented. Different deposition conditions were employed and compared in order to obtain good epitaxial $Y_2O_3$ film, furthermore importantly, to obtain good YBCO superconducting films. Following YBCO film deposited by PLD on the top of $Y_2O_3$ films have a good structure and superconducting properties. The J$_{c}$ of YBCO films on $Y_2O_3$ /Ni and $Y_2O_3$ /NiW were $1.0{\times}10^6 A/cm^2 and 1.1\times}10^6 A/cm^2$<.TEX> at 77K and self-field respectively, which indicated that $Y_2O_3$ is a suitable candidate as a single buffer layer for the fabrication of YBCO coated conductor.r.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.6-8
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• 2005

The optical and electrical properties of indium tin oxide (ITO) thin films deposited at room temperature can be substantially enhanced by adopting a two-step process. In the first step, the films (50 nm thick) were grown by pulsed laser deposition (PLD) on glass substrate at room temperature and quickly annealed at $400^{\circ}C$ in nitrogen ambient for 1 minute by using rapid thermal annealing method. The process was completed by additional deposition (150 nm thick) on annealed film at room temperature. High quality ITO films grown by two-step process at room temperature could be obtained with the resistivity of $3.02{\times}10^{-4}{\Omega}cm$, the carrier mobility of 32.07 $cm^2/Vs$, and the transparency above 90 % in visible region mainly due to the enhancement of the film crystallinity and the increase of grain size.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.273-277
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• 2015

We investigated secondary electron emission characteristics of ZnO thin films prepared by pulsed laser deposition method with respect to the ambient oxygen pressure and the substrate temperature during the deposition. X-ray diffraction, UV-Vis spectrometry, atomic force microscopy, and ${\gamma}$-FIB were used to examine the structural, optical transmission, surface morphology, and secondary electron emission properties of the films, respectively. The secondary electron emission coefficient of the ZnO films increases as the O/Zn ratio of the films increases which was thought to result from either the ambient oxygen pressure increase or the substrate temperature decrease and as the grain size of the films decreases. It was confirmed that ZnO has better secondary electron emission characteristics than those of MgO, which is currently widely used as a material for PDP protecting layers.