• Title/Summary/Keyword: ITO Deposition

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Parametric Studies of Pulsed Laser Deposition of Indium Tin Oxide and Ultra-thin Diamond-like Carbon for Organic Light-emitting Devices

  • Tou, Teck-Yong;Yong, Thian-Khok;Yap, Seong-Shan;Yang, Ren-Bin;Siew, Wee-Ong;Yow, Ho-Kwang
    • Journal of the Optical Society of Korea
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    • v.13 no.1
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    • pp.65-74
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    • 2009
  • Device quality indium tin oxide (ITO) films are deposited on glass substrates and ultra-thin diamond-like carbon films are deposited as a buffer layer on ITO by a pulsed Nd:YAG laser at 355 nm and 532 nm wavelength. ITO films deposited at room temperature are largely amorphous although their optical transmittances in the visible range are > 90%. The resistivity of their amorphous ITO films is too high to enable an efficient organic light-emitting device (OLED), in contrast to that deposited by a KrF laser. Substrate heating at $200^{\circ}C$ with laser wavelength of 355 nm, the ITO film resistivity decreases by almost an order of magnitude to $2{\times}10^{-4}\;{\Omega}\;cm$ while its optical transmittance is maintained at > 90%. The thermally induced crystallization of ITO has a preferred <111> directional orientation texture which largely accounts for the lowering of film resistivity. The background gas and deposition distance, that between the ITO target and the glass substrate, influence the thin-film microstructures. The optical and electrical properties are compared to published results using other nanosecond lasers and other fluence, as well as the use of ultra fast lasers. Molecularly doped, single-layer OLEDs of ITO/(PVK+TPD+$Alq_3$)/Al which are fabricated using pulsed-laser deposited ITO samples are compared to those fabricated using the commercial ITO. Effects such as surface texture and roughness of ITO and the insertion of DLC as a buffer layer into ITO/DLC/(PVK+TPD+$Alq_3$)/Al devices are investigated. The effects of DLC-on-ITO on OLED improvement such as better turn-on voltage and brightness are explained by a possible reduction of energy barrier to the hole injection from ITO into the light-emitting layer.

Nonhomogeneity of the Electrical Properties with Deposition Position in an ITO Thin Film Deposited under a Given R.F. Magnetron Sputtering Condition (동일 증착 조건의 스퍼터링에 의해서 제작된 Indium Tin 산화물 박막의 증착위치에 따른 전기적 특성의 불균질성)

  • 유동주;최시경
    • Journal of the Korean Ceramic Society
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    • v.38 no.11
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    • pp.973-979
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    • 2001
  • Tin-doped indium oxide (ITO) thin films were deposited using r.f. magnetron reactive sputtering and the electrical properties, such as the resistivity, carrier concentration and mobility, were investigated as a function of the sample position under a given magnetron sputtering condition. The nonhomogeneity of the electrical properties with the sample position was observed under a given magnetron sputtering condition. The resistivity of ITO thin film on the substrate which corresponded to the center of the target had a minimum value, 2∼4$\times$10$\^$-4/$\Omega$$.$cm, and it increased symmetrically when the substrate deviated from the center. The density measurement result also showed that ITO thin film deposited at the center has a maximum density of 7.0g/cm$^3$, which was a relative density of about 97%, and the density decreased symmetrically as the substrate deviated from the center. The nonhomogeneity of electrical properties with the deposition position could be explained with the incidence angle of the source beam alpha, which is related with an atomic self-shadowing effect. It was confirmed experimentally that the density in film affect both the carrier mobility and the conductivity. In the case where the density of ITO thin film is 7.0g/cm$^3$, the magnitude of the mean free path was identical with that of the grain size(the diameter of column). However, in the other cases, the mean free path was smaller than the grain size. These results showed that the scattering of the free electrons at the grain boundary is the major factor for the electrical conduction in ITO thin films having a high density, and there exists other scattering sources such as vacancies, holes, or pores in ITO thin films having a low density.ing a low density.

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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 the Korean institute of surface 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.

Influence of Post Deposition Electro-Annealing on the Properties of ITO Thin Film Deposited on a Polymer Substrate

  • Kim, Dae-Il
    • Korean Journal of Materials Research
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    • v.19 no.9
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    • pp.499-503
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    • 2009
  • Transparent ITO films were deposited on a polycarbonate substrate with RF magnetron sputtering in a pure argon (Ar) and oxygen ($O_2$) gas atmosphere, and then post deposition electro annealed for 20 minutes in a $4{\times}10^{-1}$ Pa vacuum. Electron bombardment with an accelerating voltage of 100 V increased the substrate temperature to $120^{\circ}C$. XRD analysis of the deposited ITO films did not show any diffraction peaks, while electro annealed films indicated the growth of crystallites on the (211), (222), and (400) planes. The sheet resistance of ITO films decreased from 103 to $82{\Omega}/\square$. The optical transmittance of ITO films in the visible wavelength region increased from 85 to 87%. Observation of the work function demonstrated that the electro-annealing increased the work function of ITO films from 4.4 to 4.6 eV. The electro annealed films demonstrated a larger figure of merit of $3.0{\times}10^{-3}{\Omega}^{-1}$ than that of as deposited films. Therefore, the electro annealed films had better optoelectrical performances than as deposited ITO films.

Influence of Deposition Pressure on Optical and Electrical Properties of ITO/Al/ITO Thin Films on PET by RF Magnetron Sputtering (RF magnetron sputter에 의한 PET기판상 ITO/Al/ITO 박막의 증착 압력이 광학적 전기적 특성에 미치는 영향)

  • Seo Jung-Eun;Kim Sang-Ho;Lee In-Seon;Kim Dong-Won
    • Journal of the Korean institute of surface engineering
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    • v.38 no.2
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    • pp.69-72
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    • 2005
  • ITO-Al-ITO multi-layers were deposited at room temperature by RF magnetron sputtering on polyethylene terephthalate (PET). The films were deposited at various pressures of $8\times10^{-4},\;1\times10^{-3},\;4\times10^{-3},\;8\times10^{-3}\;and\;1\times10^{-2}$ Torr. A correlation between microstructure and electro-optical properties was studied. Films deposited? at low pressure have higher transmission, and lower reflectance and resistance than film deposited at high pressure. Sheet resistance, transmission, and reflectance were $141.6\Omega/\Box\;88\%\;and\;6.8\%$ resectively when the deposition pressure was $8\times10^{-4}$ torr, that was the optimum condition.

Characteristics of OLED Lifetime by ITO/glass Substrate Pre-treatment and Cathode Deposition Methods (ITO/glass 기판 전처리와 음극 전극 증착방법에 따른 OLED 수명 특성)

  • Shin, Se-Jin;Jang, Ji-Geun;Kim, Min-Young
    • Journal of the Semiconductor & Display Technology
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    • v.7 no.2
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    • pp.59-62
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    • 2008
  • The Lifetime of OLEDs by ITO/glass substrates cleaning method and cathode deposition method were investigated in the fabrication of green light emitting OLEDs with $Alq_3$-C545T fluorescent system. In our experiments, the optimum cleaning method was obtained at last processing of boiling IPA(isopropyl alcohol). And the optimum deposition methode was obtained at 3 steps deposition rate of Al. The deposition rate of 3 steps progressed changing from $0.5\AA$/sec to $3\AA$/ sec. The green light emitting OLED with plasma treatment at 150W for 2 minutes showed the highest luminance and efficiency of 20000 cd/$m^2$ and 16 lm/W. On the contrary, the OLED device without plasma treatment showed much lower performance with the luminance and efficiency of 3500 cd/$m^2$ and 2 lm/W.

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Chromaticity(b*), Sheet Resistance and Transmittance of SiO2-ITO Thin Films Deposited on PET Film by Using Roll-to-Roll Sputter System (롤투롤시스템을 이용하여 PET 필름위에 제조된 SiO2-ITO 박막의 색도(b*), 면저항과 투과도 연구)

  • Park, Mi-Young;Kang, Bo-Gab;Kim, Jung-Soo;Kim, Hye-Young;Kim, Hu-Sik;Lim, Woo-Taik;Choi, Sik-Young
    • Korean Journal of Materials Research
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    • v.21 no.5
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    • pp.255-262
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    • 2011
  • This paper has relatively high technical standard and experimental skill. The fabrication of TCO film with high transparency, low resistance and low chromaticity require exact control of several competing factors. This paper has resolved these problems reasonably well, thus recommended for publication. Indium tin oxide(ITO) thin films were by D.C. magnetron roll-to-roll sputter system utilizing ITO and $SiO_2$ targets of ITO and $SiO_2$. In this experiment, the effect of D.C. power, winding speed, and oxygen flow rate on electrical and optical properties of ITO thin films were investigated from the view point of sheet resistance, transmittance, and chromaticity($b^*$). The deposition of $SiO_2$ was performed with RF power of 400W, Ar gas of 50 sccm and the deposition of ITO, DC power of 600W, Ar gas of 50 sccm, $O^2$ gas of 0.2 sccm, and winding speed of 0.56m/min. High quality ITO thin films without $SiO_2$ layer had chromaticity of 2.87, sheet resistivity of 400 ohm/square, and transmittance of 88% and $SiO_2$-doped ITO Thin film with chromaticity of 2.01, sheet resistivity of 709 ohm/square, and transmittance of more than 90% were obtained. As a result, $SiO_2$ was coated on PET before deposition of ITO, their chromaticity($b^*$) and transmittance were better than previous results of ITO films. These results show that coating of $SiO_2$ induced arising chromaticity($b^*$) and transmittance. If the thickness of $SiO_2$ is controlled, sheet resistance value of ITO film will be expected to be better for touch screen. A four point probe and spectrophotometer are used to investigate the properties of ITO thin films.

The Characterization of Structural and Optical Properties for rf Magnetron Sputtered $(BaSr)TiO_3$ Thin Film (Rf Magnetron Sputtering 방법에 의하여 제조된 $(BaSr)TiO_3$ 박막의 구조적, 광학적 특성 고찰)

  • Kim, Tae-Song;Oh, Myung-Hwan;Kim, Chong-Hee
    • Analytical Science and Technology
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    • v.6 no.2
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    • pp.239-246
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    • 1993
  • The structure of $(BaSr)TiO_3$ thin film deposited on ITO coated glass, bare glass and (100) Si substrates was not changed, but the crystallinity was improved by the polycrystalline ITO layer and (100) Si substrate. The composition of $(BaSr)TiO_3$ thin film deposited on ITO coated glass was nearly stoichiometric ((Ba+Sr)/Ti=1.08~1.09) and very uniform through all deposition process. But as the deposition temperature increases, the interdiffusion between grown thin film and ITO layer and between ITO layer and base glass is severer. $(BaSr)TiO_3$ thin film deposited on ITO coated glass substrate was highly transparent. The refractive index($n_f$) of $(BaSr)TiO_3$ thin film deposited on ITO coated glass was 2.138~2.286 as a function of substrate temperature.

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Excellent properties of Indium Tin Oxide-Carbon Nano tube Nano composites at low temperatures by Nano Cluster Deposition technique

  • Pammi, S.V.N.;Park, Jong-Hyun;Chanda, Anupama;Park, Yeon-Woong;Ahn, Jun-Ku;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.7-7
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    • 2010
  • Indium tin oxide (ITO) - SWNT nano crystalline composites was synthesized at low temperature(${\sim}250^{\circ}C$)using Nano Cluster Deposition technique by Metal Orhoganic Chemical Vapor Deposition method. XRD patterns of ITO- SWNT composite shows pure cubic phases without any secondary phase. I-V measurement gives resistance of 12 ohms for Sn doped (3 wt %) indium oxide-SWNT composites. The electrical conductivity of the nano composites is significantly enhanced compared to the SWNT.

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Optical and Hydrophobic Properties of Ag Deposited ZnO Nanorods on ITO/PET (ITO/PET 기판 위에 성장된 산화아연 나노로드에 형성된 은 입자의 광학적 특성 및 소수성 표면 연구)

  • Ko, Yeong-Hwan;Kim, Myung-Sub;Yu, Jae-Su
    • Journal of the Korean Vacuum Society
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    • v.21 no.4
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    • pp.205-211
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    • 2012
  • We investigated the optical and hydrophobic properties of the deposited silver (Ag) zinc oxide (ZnO) nanorods (NRs) on flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates (i.e., ITO/PET). The ZnO NRs were grown by an electrochemical deposition using a sputtered ZnO seed layer and the Ag was deposited by using a thermal evaporator. For comparison, the same fabrication process was carried out on the bare ITO/PET without ZnO NRAs. Due to the discrete surface of ZnO NRs, the deposited Ag was formed as nano-scale particles, while the Ag became film-like for bare ITO/PET. In order to control the size and amount of Ag particles, the Ag deposition time was changed from 100 to 600 s. When the deposition time was increased, the Ag particles became larger and denser, and the absorptance was increased. This enhanced absorptance may be due to the localized surface plasmon resonance of Ag particles. Furthermore, the relatively high hydrophobicity was observed for the deposited Ag on the ZnO NRs/ITO/PET. These improved optical and surface properties are expected to be useful for flexible photovoltaic and optoelectronic devices.