• Title/Summary/Keyword: GZO thin films

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Effect of Ar Flow Ratio on the Characteristics of Ga-Doped ZnO Grown by RF Magnetron Sputtering (마그네트론 스퍼터를 이용한 Ar 가스 유량 조절에 따른 GZO의 특성 변화)

  • Jeong, Youngjin;Lee, Seungjin;Son, Changsik
    • 한국신재생에너지학회:학술대회논문집
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    • pp.62.1-62.1
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    • 2011
  • The structural, optical, and electrical properties of Ga-doped ZnO (GZO) thin films on glass substrates grown by radio-frequency(RF) magnetron sputtering were investigated. The flow ratio of Ar was varied as a deposition parameter for growing high-quality GZO thin films. The structural properties and surface morphologies of GZO were characterized by the X-ray diffraction. To analyze the optical properties of GZO, the optical absorbance was measured in the wavelength range of 300-1100 nm by using UV-VIS spectrophotometer. The optical transmittance, absorption coefficient, and optical bandgap energy of GZO thin films were calculated from the measured data. The crystallinity of GZO thin films is improved and the bandgap energy increases from 3.08 to 3.23eV with the increasing Ar flow ratio from 10 to 100 sccm. The average transmittance of the films is over 88% in the visible range. The lowest resistivity of the GZO is $6.215{\times}10^{-4}{\Omega}{\cdot}cm$ and the hall mobility increases with the increasing Ar flow ratio. We can optimize the characteristics of GZO as a transparent electrode for thin film solar cells by controlling Ar flow ratio during deposition process.

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Effect of Deposition Temperature on Structural and Electrical Properties of Ga-Doped ZnO for Transparent Electrode of Thin Film Solar Cells (박막 태양전지용 투명 전극을 위한 Ga 도핑된 ZnO의 증착 온도에 따른 구조 및 전기 특성 변화)

  • Son, Chang-Sik
    • Korean Journal of Materials Research
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    • v.21 no.3
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    • pp.144-148
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    • 2011
  • We have investigated the structural and optical properties of Ga-doped ZnO (GZO) thin films deposited by RF magnetron sputtering at various deposition temperatures from 100 to $500^{\circ}C$. All the GZO thin films are grown as a hexagonal wurtzite phase with highly c-axis preferred parameter. The structural and electrical properties are strongly related to deposition temperature. The grain size increases with the increasing deposition temperature up to $400^{\circ}C$ and then decreases at $500^{\circ}C$. The dependence of grain size on the deposition temperature results from the variation of thermal activation energy. The resistivity of GZO thin film decreases with the increasing deposition temperature up to $300^{\circ}C$ and then decreases up to $500^{\circ}C$. GZO thin film shows the lowest resistivity of $4.3{\times}10^{-4}\;{\Omega}cm$ and highest electron concentration of $1.0{\times}10^{21}\;cm^{-3}$ at $300^{\circ}C$. The mobility of GZO thin films increases with the increasing deposition temperature up to $400^{\circ}C$ and then decreases at $500^{\circ}C$. GZO thin film shows the highest resistivity of 14.1 $cm^2/Vs$. The transmittance of GZO thin films in the visible range is above 87% at all the deposition temperatures. GZO is a feasible transparent electrode for the application to the transparent electrode of thin film solar cells.

Effects of Doping Concentration on the Properties of Ga-doped ZnO Thin Films Prepared by RF Magnetron Sputtering (Ga의 도핑농도에 따른 ZnO 박막의 특성)

  • Kim, Hyoung Min;Ma, Dae Young;Park, Ki Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.12
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    • pp.984-989
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    • 2012
  • We have investigated the structural, electrical and optical properties of Ga-doped ZnO (GZO) thin films prepared by RF magnetron sputtering with laboratory-made ZnO targets containing 1, 3, 5, 7 wt% of $Ga_2O_3$ powder as a doping source. The GZO thin films show the typical crystallographic orientation with c-axis regardless of $Ga_2O_3$ content in the targets. The $3,000{\AA}$ thick GZO thin films with the lowest resistivity of $7{\times}10^{-4}{\Omega}{\cdot}cm$ are obtained by using the GZO ($Ga_2O_3$= 5 wt%) target. Optical transmittance of all films shows higher than 80% at the visible region. The optical energy band gap for GZO films increases as the carrier concentration ($n_e$) in the film increases.

Properties of Sputtered Ga Doped ZnO Thin Film Under Various Reaction Gas Ratio (Reaction Gas 변화에 따라 스퍼터된 Ga Doped ZnO 박막의 특성)

  • Kim, Jong-Wook;Kim, Hong-Bae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.4
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    • pp.289-293
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    • 2013
  • We have studied structural, optical, and electrical properties of the Ga-doped ZnO (GZO) thin films being usable in transparent conducting oxides. The GZO thin films were deposited on the corning 1737 glass plate by the RF magnetron sputtering system. To find optimal properties of GZO for transparent conducting oxides, the Ar gas in sputtering process was varied as 40, 60, 80 and 100 sccm, respectively. As reaction gas decreased, the crystallinity of GZO thin film was increased, the optical bandgap of GZO thin film increased. The transmittance of the film was over 80% in the visible light range regardless of the changes in reaction gas. The measurement of Hall effect characterizes the whole thin film as n-type, and the electrical property was improved with decreasing reaction gas. The structural, optical, and electrical properties of the GZO thin films were affected by Ga dopant content in GZO thin film.

Sensing properties of ZnO thin films fabricated by RF sputtering method for toxic gas (RF sputtering 방법을 이용하여 제작한 ZnO 박막의 유독성 가스에 대한 반응 특성 연구)

  • Hwang, Hyun-Suk;Kang, Hyun-Il;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.247-247
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    • 2009
  • In this work, Ga-doped ZnO (GZO) thin films for toxic gas sensor application were deposited on low temperature co-fired ceramic (LTCC) substrates, by RF magnetron sputtering method. LTCC is one of promising materials for integration with heater, low cost production and high manufacturing yields than silicon substrate. The LTCC substrates with thickness of $400\;{\mu}m$ were fabricated by laminating 12 greentapes which consist of alumina and glass particle in an organic binder. The GZO thin films deposited on the substrates and were analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The films are well crystallized in the hexagonal (wurzite) structure with increasing thickness. The fabricated sensors showed good sensitivity and fast response time to common types of toxic gases (NOx, COx).

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Properties of GZO thin films prepared by oxygen gas flow rate (산소 분압비에 따라 제작된 GZO 박막의 특성)

  • Jung, Yu-Sup;Kim, Kyung-Hwan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.336-336
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    • 2010
  • Ga doped ZnO (GZO) transparent conductive films were deposited on the glass substrates at room temperature by facing target sputtering (FTS) method. The sputtering targets were 100 mm diameter disks of GZO($Ga_2O_3$ 3.w.t%) and Zn metal. The GZO thin films were deposited as a various $PO_2$ (oxygen gas content). Base pressure was $2{\times}10^{-6}$torr, and a working pressure was 1mTorr. The properties of thin films on the electrical and optical properties of the deposited films were investigated by using a four-point probe, a Hall Effect measurement and an UV/VIS spectrometer. The minimum resistivity of film was $6.5{\times}10^{-4}$[$\Omega$-cm] and the average transmittance of over 80% was seen in the visible range.

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Effect of RF Power on Structural and Electrical Properties of Ga-Doped ZnO for Transparent Electrode of Thin Film Solar Cells (박막 태양전지용 투명 전극을 위한 Ga 도핑된 ZnO의 RF 전력에 따른 구조 및 전기 특성 변화)

  • Son, Chang-Sik
    • Korean Journal of Materials Research
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    • v.21 no.4
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    • pp.202-206
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    • 2011
  • We have investigated the structural and electrical properties of Ga-doped ZnO (GZO) thin films deposited by an RF magnetron sputtering at various RF powers from 50 to 90W. All the GZO thin films are grown as a hexagonal wurtzite phase with highly c-axis preferred parameters. The structural and electrical properties are strongly related to the RF power. The grain size increases as the RF power increases since the columnar growth of GZO thin film is enhanced at an elevated RF power. This result means that the crystallinity of GZO is improved as the RF power increases. The resistivity of GZO rapidly decreases as the RF power increases up to 70 W and saturates to 90W. In contrast, the electron concentration of GZO increases as the RF power increases up to 70 W and saturates to 90W. GZO thin film shows the lowest resistivity of $2.2{\times}10^{-4}{\Omega}cm$ and the highest electron concentration of $1.7{\times}10^{21}cm^{-3}$ at 90W. The mobility of GZO increases as the RF power increases since the grain boundary scattering decreases due to the reduced density of the grain boundary at a high RF power. The transmittance of GZO thin films in the visible range is above 90%. GZO is a feasible transparent electrode for application as a transparent electrode for thin film solar cells.

Effects of Doping Concentrations and Annealing Temperatures on the Electrical and Optical Properties of Ga-doped ZnO Thin Films by Sol-gel Method (Sol-gel 법으로 제작한 Ga-doped ZnO 박막의 도핑 농도와 열처리 온도가 전기적 및 광학적 특성에 미치는 효과)

  • Kang, Seong-Jun;Joung, Yang-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.3
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    • pp.558-564
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    • 2012
  • We fabricated Ga doped ZnO (GZO) thin films on the glass substrate (Eagle 2000) with various of Ga doping concentration and annealing temperatures using sol-gel method, electrical and optical properties were investigated. When the GZO thin films doped with 1 mol% of Ga and annealed at $600^{\circ}C$, the excellent (002) orientation was observed. In the results of Hall measurement, carrier concentration decreased and resistivity increased due to segregation effect with increasing of the Ga doping concentration. The largest carrier concentration and lowest resistivity were $9.13{\times}10^{18}cm^{-3}$ and $0.87{\Omega}cm$, respectively, in the GZO thin films doped with 1 mol% Ga and annealed at $600^{\circ}C$. All films is higher than 80 % in the visible light region. Energy band gap narrowing due to Burstein-Moss effect was observed with increasing of Ga doping concentration from 1 to 4 mol%.

Effects of RF power on the Electrical and Optical Properties of GZO Thin Films Deposited on Flexible Substrate (RF 파워가 플렉시블 기판에 성장시킨 GZO 박막의 전기적 및 광학적 특성에 미치는 영향)

  • Joung, Yang-Hee;Kang, Seong-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2497-2502
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    • 2014
  • The 5 wt.% Ga-doped zinc oxide (GZO) thin films were fabricated on PES substrates with various RF power 50~80 W by using RF magnetron sputtering in order to investigate the optical and electrical properties of GZO thin films. The XRD measurement showed that GZO thin films exhibit c-axis orientation. At a RF power of 70W, the GZO thin film showed the highest (002) diffraction peak with a Full-Width-Half-Maximum (FWHM) of $0.44^{\circ}$. AFM analysis showed that the lowest surface roughness (0.20 nm) was obtained for the GZO thin film fabricated at 70 W of RF power. The electrical property indicated that the minimum resistivity ($6.93{\times}10^{-4}{\Omega}{\cdot}cm$) and maximum carrier concentration ($7.04{\times}10^{20}cm^{-3}$) and hall mobility ($12.70cm^2/Vs$) were obtained in the GZO thin film fabricated at 70W of RF power. The optical transmittance in the visible region was higher than 80 %, regardless of RF power. The optical band-gap showed the slight blue-shift with increased in carrier concentration which can be explained by the Burstein-Moss effect.

Electrical and Optical Properties of the GZO Transparent Conducting Layer Prepared by Magnetron Sputtering Technique (마그네트론 스퍼터링법으로 제작된 GZO 투명전도막의 전기적 및 광학적 특성)

  • No, Im-Jun;Kim, Sung-Hyun;Shin, Paik-Kyun;Lee, Kyung-Il;Kim, Sun-Min;Cho, Jin-Woo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.4
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    • pp.110-115
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    • 2010
  • Transparent conducting gallium-doped zinc oxide (GZO) thin films which were deposited on Corning glass substrate using an Gun-type rf magnetron sputtering deposition technology. The GZO thin films were fabricated with an GZO ceramic target (Zn : 97[wt%], $Ga_2O_3$ : 3[wt%]). The GZO thin films were deposited by varying the growth conditions such as the substrate temperature, oxygen pressure. Among the GZO thin films fabricated in this study, the one formed at conditions of the substrate temperature of 200[$^{\circ}C$], Ar flow rate of 50[sccm], $O_2$ flow rate of 5[sccm], rf power of 80[W] and working pressure of 5[mtorr] showed the best properties of an electrical resistivity of $2.536{\times}10^{-4}[{\Omega}{\cdot}cm]$, a carrier concentration of $7.746{\times}10^{20}[cm^{-3}]$, and a carrier mobility of 31.77[$cm^2/V{\cdot}S$], which indicates that it could be used as a transparent electrode for thin film transistor and flat panel display applications.