• Title/Summary/Keyword: $RfC_w$

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Sputter Deposition and Surface Treatment of $TiO_{2}$ films for Dye-Sensitized Solar Cells using Reactive RF Plasma (RF 스퍼터링 증착된 $TiO_{2}$ 박막의 염료감응형 태양전지 적용 연구)

  • Kim, Mi-Jeong;Seo, Hyun-Woong;Choi, Jin-Young;Jo, Jae-Suk;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.309-312
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    • 2007
  • Sputter deposition followed by surface treatment was studied using reactive RF plasma as a method for preparing titanium oxide($TiO_{2}$) films on indium tin oxide(ITO) coated glass substrate for dye-sensitized solar cells(DSSCs). Anatase structure $TiO_{2}$ films deposited by reactive RF magnetron sputtering under the conditions of $Ar/O_{2}$(5%) mixtures, RF power of 600W and substrate temperature of $400^{\circ}C$ were surface-treated by inductive coupled plasma(ICP) with $Ar/O_{2}$ mixtures at substrate temperature of $400^{\circ}C$, and thus the films were applied to the DSSCs, The $TiO_{2}$ Films made on these exhibited the BET specific surface area of 95, the pore volume of $0.3cm^{2}$ and the TEM particle size of ${\sim}25$ nm. The DSSCs made of this $TiO_{2}$ material exhibited an energy conversion efficiency of about 2.25% at $100mW/cm^{2}$ light intensity.

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Effect of Gum Addition on the Rheological Properties of Rice Flour Dispersions

  • Chun, So-Young;Kim, Hyung-Il;Yoo, Byoung-Seung
    • Food Science and Biotechnology
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    • v.15 no.4
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    • pp.589-594
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    • 2006
  • The effect of five commercial gums (carboxylmethylcellulose, CMC; guar gum, GG; hydroxypropylmethyl-cellulose, HPMC; locust bean gum, LBG; and xanthan gum) at a concentration of 0.25% on the rheological properties of rice flour (RF) dispersions was investigated in steady and dynamic shear. The steady shear rheological properties showed that RF gum mixture dispersions (5%, w/w) at $25^{\circ}C$ had high shear-thinning flow behavior (n=0.20-0.31) exhibiting a yield stress. Magnitudes of consistency index (K), apparent viscosity (${\eta}_{a,100}$), and Casson yield stress (${\sigma}_{oc}$) of RF-gum mixtures were much higher than those of RF dispersion with no added gum (control). Activation energy values (6.67-10.8 kJ/mole) of RF-gum mixtures within the temperature range of $25-70^{\circ}C$ were lower than that (11.9 kJ/mole) of the control. Dynamic rheological data of log (G', G") versus log frequency (${\omega}$) of RF-gum mixtures had positive slopes (0.15-0.37) with G' greater than G" over most of the frequency range (0.63-63 rad/sec), demonstrating a frequency dependency. Tan ${\delta}$ (G"/G') values of RF-gum mixtures, except for xanthan gum, were much higher than that of the control.

Characteristics of Diamond Like Carbon Thin Film Deposited by Plasma Enhanced Chemical Vapor Deposition Method with Gas Flow Rate and Radio Frequency Power (가스 유량과 RF Power에 따라 PECVD 방법으로 증착된 DLC 박막의 특성)

  • Jeong, Seon-Yeong;Kim, Hyeon-Gi;Ju, Seong-Hu
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.88-88
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    • 2018
  • DLC(Diamond Like Carbon) 박막은 높은 열전도도, 큰 전기저항, 높은 강도 등의 다이아몬드와 유사한 특성을 가지고 있으면서 저온 저압에서도 합성이 가능하고, 합성 조건에 따라 물리 화학적 특성도 넓게 조절 할 수 있으며 상대적으로 넓은 면적에서 균일하고 평활한 박막의 합성이 가능하여 산업적 응용 면에서도 경쟁력을 갖추고 있다[1]. 이러한 DLC 박막을 합성함에 있어서 RF-PECVD(Radio Frequency Plasma Enhanced Chemical Vapor Deposition) 방법은 PECVD 방법 중 가장 보편적으로 사용되고 또 캐패시터 타입의 RF-PECVD 방법은 균일한 대면적 증착과 대량생산이 가능하다[1,2]. 본 연구에서는 우수한 특성을 갖는 DLC 박막의 증착 조건을 찾기 위해 캐패시터 타입의 RF-PECVD를 사용하여 공정 가스의 유량과 RF Power를 변화하여 박막을 증착하고, 증착된 박막의 특성을 연구하였다. DLC 박막은 ITO(Indium Tin Oxide) 유리 기판 위에 $100^{\circ}C$에서 5 min 동안 아세틸렌($C_2H_2$) 가스를 사용하여 가스 유량과 RF Power를 변화하여 증착하였다. 증착된 DLC 박막의 특성은 투과도, 평탄도, 두께를 측정하여 비교하였다. 가시광선 영역(380-780 nm)에서 투과도를 측정한 결과 ITO 유리 기판을 기준으로 한 DLC 박막의 투과도는 가시광선 영역 평균 94.8~98.8% 사이의 값으로 매우 높은 투과율을 나타내었다. 투과도는 가스 유량이 증가함에 따라 증가하는 경향을 나타내었고, RF Power의 변화에는 특정한 변화를 나타내지 않았다. 박막의 평탄도($R_a$, $R_{rms}$)와 두께는 AFM(Atomic Force Microscope)을 사용하여 측정하였다. 평탄도 $R_{rms}$는 0.8~3.3 nm, $R_a$는 0.6~2.5 nm 사이를 나타내었고 RF Power와 가스 유량의 변화에 따른 경향성을 나타내지는 않았다. 두께는 RF Power 25 W에서 55 W로 증가함에 따라 증가하는 경향을 나타내었으나 70W에서는 가스의 유량에 따라 상이한 결과를 나타내었다.

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Effect of RF Superimposed DC Magnetron Sputtering on Electrical and Bending Resistances of ITO Films Deposited on PET at Low Temperature (DC마그네트론 스퍼터링법으로 PET 기판위에 저온 증착한 ITO박막의 비저항과 굽힘 저항성에 대한 RF인가의 영향)

  • Park, Mi-Rang;Lee, Sung-Hun;Kim, Do-Geun;Lee, Gun-Hwan;Song, Pung-Keun
    • Journal of Surface Science and Engineering
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    • v.41 no.5
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    • pp.214-219
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    • 2008
  • Indium tin oxide (ITO) films were deposited on PET substrate by RF superimposed DC magnetron sputtering using ITO (doped with 10 wt% $SnO_2$) target. Substrate temperature was maintained below $750^{\circ}C$ without intentionally substrate heating during the deposition. The discharge voltage of DC power supply was decreased from 280 V to 100 V when superimposed RF power was increased from 0 W to 150 W. The electrical properties of the ITO films were improved with increasing of superimposed RF power. In the result of cyclic bending test, relatively high mechanical property was obtained for the ITO film deposited with RF power of 75 W under DC current of 0.75 A which could be attributed to the decrease of internal stress caused by decrease in both deposition rate and plasma impedance.

A study on c-axis preferred orientation at a various substrate temperature of ZnO thin film deposited by RF magnetron sputtering (RF magnetron sputtering법으로 ZnO박막 제조시 기판온도에 따른 c축 배향성에 관한 연구)

  • 이종덕;송준태
    • Electrical & Electronic Materials
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    • v.9 no.2
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    • pp.196-203
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    • 1996
  • The highly c-axis oriented zinc oxide thin films were deposited on Sapphire(0001) substrates by reactive RF magnetron sputtering. The characteristics of zinc oxide thin films on RF power, substrate-target distance, and substrate temperature were investigated by XRD, SEM and EDX analyses. The physical characteristics of zinc oxide thin films changed with various deposition conditions. The higher substrate temperatures were, The better crystallinity of zinc oxide thin films. The highly c-axis oriented zinc oxide thin films were obtained at sputter pressure 5mTorr, rf power 200W, substrate temperature 350.deg. C, substrate-target distance 5.5cm. In these conditions, the resistivity of zinc oxide thin films deposited on pt/sapphire was 12.196*10$^{9}$ [.ohm.cm].

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Optical E-H Transition Properties of Inductively Coupled Plasma with Ar Gas Pressure and RF Pourer (Ar 가스 압력과 RF 전력변화에 따른 유도결합형ㆍ플라즈마 E-H모드 변환의 광학적 특성)

  • 허인성;조주웅;이영환;김광수;최용성;박대희
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.1
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    • pp.20-23
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    • 2004
  • In this paper, the emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma. To transmit the electromagnetic energy into the chamber, a RF power of 13.56 [MHz] was applied to the antenna and considering the Ar gas pressure and the RF electric power change, the emission spectrum, Ar I line, luminance were investigated. At this time, the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10∼60 [mTorr], 10∼300 [W], respectively. From emission intensity and lumnance intensity results, the mode transition from E-mode to H-mode was observed. This implies that this method can be used to find an optimal RF power for efficient light illumination in an electrodeless fluorescent lamp.

XPS Analysis of TiNx Thin Films by RF Magnetron Sputtering (RF magnetron 스파터링법으로 제작한 TiNx 박막의 XPS 분석)

  • Park, Moon Chan;Oh, Jeong Hong;Hwangbo, Chang Kwan
    • Journal of Korean Ophthalmic Optics Society
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    • v.3 no.1
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    • pp.115-120
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    • 1998
  • The $TiN_x$ thin films were prepared on glass substrate by RF(radio-frequency) magnetron sputtering apparatus from a Ti target in a gaseous mixture of argon and nitrogen. In deposition, a RF power supply was used as a power source with a constant power of 240W, and the substrate was heated to $200^{\circ}C$. The films were obtained at nitrogen flow rates in the range 3-9 seem with a constant argon flow rate of 20 seem. For the films obtained, the chemical binding energy of the films was investigated by XPS (x-ray photoelectron spectroscopy) in order to analyze the chemical nature and composition of the films.

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Sheet Reisistance Analysis of TiNx Thin Film by RF Magnetron Sputtering (RF magnetron 스파터링법으로 제작한 TiNx 박막의 면저항분석)

  • Park, Moon Chan;Oh, Jeong Hong;Kim, Nam Young;Hwangbo, Chang Kwon
    • Journal of Korean Ophthalmic Optics Society
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    • v.4 no.1
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    • pp.21-25
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    • 1999
  • The TiN, thin films were prepared on glass substrate by RF(radio-frequency) magnetron sputtering apparatus from a Ti target in a gaseous mixture of argon and nitrogen. In deposition, a RF power supply was used as a power source with a constant power of 240W, and the substrate was heated to $200^{\circ}C$. The films were obtained at nitogen flow rates in the range 3-9 sccm with a constant argon flow rate of 20 secm. For the films obtained, the sheet resistance and the chemical binding energy of the films was observed by four-point-probe method and x-ray photoelectron spectroscopy(XPS) depth profiling respectively. In addition, we investigated the relationship between the surface resistance and the chemical nature of the films.

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Implementation of Ladder Type SAW Filters for Mobile Communication (이동통신 시스템을 위한 사다리형 표면탄성파 필터의 구현)

  • 이택주;정덕진
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.3
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    • pp.1-9
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    • 2003
  • In this paper, we designed a highly suppressed sidelobe ladder type RF SAW bandpass filter based on 1-port resonator, for 800 MHz mobile communication system. In order to get the highest device characteristics, we optimized some important parameters such as the electrode thickness, electrode lambda weghting of the reflectors, and static capacitance ratio. Furthermore, we fabricated the Tx and Rx. filter using optimized parameters. Implemented filters can be used in 800 MHz mobile communication system and external impedance matching circuits are not needed. RF filter was fabricated on 36$^{\circ}$LiTaO$_3$ substrates with Al-Cu (W 3 %)and mounted 3.8mm$\times$3.8mm$\times$1.5mm SMD package. Developed filters has 2.3 dB insertion loss in the 25 MHz pass-band, 33MHz with 3-dB insertion loss, stop-band rejection of 30 dB, passband ripple is less than 0.5 The power durability of the filters measured about 3.5W and the maximum temperature variation within -2$0^{\circ}C$~8$0^{\circ}C$ was 0.09 dB/$^{\circ}C$ of 3-dB insertion loss.

A Study of Thin Film deposition using of RF Magnetron Sputtering (RF 마그네트론 스퍼터링을 이용한 박막 증착에 관한 연구)

  • Lee, Woo Sik
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.6
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    • pp.772-777
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    • 2018
  • This paper used RF Magnetron Sputtering to deposition n-type and p-type to ITO glass. The N-type ohmic contact worked well under all conditions. Sheet resistance has been shown to increase sheet resistance as RF Power increases. After analyzing the surface of the deposited thin film, in the condition that RF Power was 250W and substrate temperature was $250^{\circ}C$, particles were measured to have a uniform and consistent thin film. P-type has good ohmic contact under all conditions and sheet resistance has been shown to increase as RF Power increases. As the RF Power grew, thickness increased and stabilized. PN junction thin film and NP junction thin film showed increased thickness and stabilized as sputtering time increased. As a result of thin film, conversion efficiency was at 0.2 when sputtering time was 10 minutes.