• Title/Summary/Keyword: GaInZnO

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Microstructure of ZnO:Ga Thin Films by RF magnetron sputtering (RF 스퍼터링법에 의한 ZnO:Ga 박막의 미세구조)

  • Kim, Byung-Sub;Lee, Sung-Wook;Lim, Dong-Gun;Park, Min-Woo;Kwak, Dong-Joo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.477-480
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    • 2004
  • Ga doped zinc oxide films (ZnO:Ga) were deposited on glass substrate by RF magnetron sputtering from a ZnO target mixed with $Ga_O_3$. The effects of RF discharge power on the electrical, optical and structural properties were investigated experimentally. The structural and electrical properties of the film are highly affected by the variation of RF discharge power. The lowest electrical resistivity of $4.9{\times}10^{-4}\;\Omega-cm$ were obtained with the film deposited from 3 wt% of $Ga_2O_3$ doped target and at 200 W in RF discharge power. The transmittance of the 900 nm thin film was 91.7% in the visible waves. The effect of annealing on the as-deposited film was also studied to improve the electrical resistivity of the ZnO:Ga film.

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Structural and Electrical Properties of Ga-doped ZnO-SnO2 Films (Ga이 첨가된 ZnO-SnO2막의 구조적 및 전기적 특성)

  • Park, Ki-Cheol;Ma, Tae-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.8
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    • pp.641-646
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    • 2011
  • Ga-doped ZnO-$SnO_2$ (ZSGO) films were deposited by rf magnetron sputtering and their structural and electrical properties were investigated. In order to fabricate the target for sputtering, the mixture of ZnO, $SnO_2$ (1:1 weight ratio) and $Ga_2O_3$ (3.0 wt%) powder was calcined at $800^{\circ}C$ for 1 h. The substrate temperature was varied from room temperature to $300^{\circ}C$. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The optical transmittances of the films were measured and the optical energy band gaps were obtained from the absorption coefficients. The resistivity variation with substrate temperature was measured. Auger electron spectroscopy was employed to find the atomic ratio of Zn, Sn, Ga and O in the film deposited at room temperature. ZSGO films exhibited the optical transmittance in the visible region of more than 80% and resistivity higher than $10\;{\Omega}cm$.

Transparent Phosphorus Doped ZnO Ohmic Contact to GaN Based LED

  • Lim, Jae-Hong;Park, Seong-Ju
    • Korean Journal of Materials Research
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    • v.19 no.8
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    • pp.417-420
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    • 2009
  • This study develops a highly transparent ohmic contact using phosphorus doped ZnO with current spreading for p-GaN to increase the optical output power of nitride-based light-emitting diodes (LEDs). The phosphorus doped ZnO transparent ohmic contact layer was prepared by radio frequency magnetron sputtering with post-deposition annealing. The transmittance of the phosphorus doped ZnO exceeds 90% in the region of 440 nm to 500 nm. The specific contact resistance of the phosphorus doped ZnO on p-GaN was determined to be $7.82{\times}10^{-3}{\Omega}{\cdot}cm^2$ after annealing at $700^{\circ}C$. GaN LED chips with dimensions of $300\times300{\mu}m$ fabricated with the phosphorus doped ZnO transparent ohmic contact were developed and produced a 2.7 V increase in forward voltage under a nominal forward current of 20 mA compared to GaN LED with Ni/Au Ohmic contact. However, the output power increased by 25% at the injection current of 20 mA compared to GaN LED with the Ni/Au contact scheme.

A Study on Transmuted Impurity Atoms formed in Neukon-Irradiated ZnO Thin films (중성자 조사한 ZnO 박막에 생성된 헥전환 불순물들fH 대한 연구)

  • Sun, Kyu-Tae;Park, Kwang-Soo;Han, Hyon-Soo;Kim, Sang-Sig
    • Proceedings of the KIEE Conference
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    • 2001.11a
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    • pp.161-164
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    • 2001
  • Transmuted impurity atoms formed in neutron-irradiated ZnO thin films were theoretically identified first and then experimentally confirmed by Photoluminescence (PL). ZnO thin films grown by plasma-assisted molecular beam epitaxy were irradiated by neutron beam at room temperature. Among eight isotropes naturely exiting in ZnO films, only $^{64}Zn$, $^{68}Zn$, $^{70}Zn$ and $^{18}O$ were expected to transmute into $^{65}Cu$, $^{69}Ga$, $^{71}Ga$ and $^{19}F$, respectively. The concentrations of these transmuted atoms were estimated by considering natural abundance, neutron fluence, and neutron cross section. The neutron-irradiated ZnO thin films were characterized by PL. In the PL spectra of these ZnO thin film, the Cu-related PL peaks were seen, but the Ga- or F-associated PL peaks were absent. This observation demonstrates the existence of $^{65}Cu$ in the ZnO. In this paper, emission mechanism of Cu impurities wil1 be described and the reason for the absence of the Ga- or F-associated PL peaks will be discussed.

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Properties of ZnO:Ga thin films deposited by RF magnetron sputtering under various RF power

  • Kim, Deok Kyu;Kim, Hong Bae
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.242-244
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    • 2015
  • ZnO:Ga thin films were deposited by RF magnetron sputtering technique from ZnO (3 wt.% $Ga_2O_3$) target onto glass substrates under various RF power. The influence of RF power on the structural, electrical, and optical properties of ZnO:Ga thin films was investigated by X-ray diffraction, atomic force microscopy, Hall method and optical transmission spectroscopy. As the RF power increases from 50 to 110W, the crystallinity is deteriorated, the root main square surface roughness is decreased and the sheet resistance is increased. The increase of sheet resistance is caused by decreasing carrier concentration due to interstitial Ga ion. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is a red-shift with increasing RF power.

Effect of Moisture on Cu(In,Ga)Se2 Solar Cell with (Ga,Al) Co-doped ZnO as Window Layer ((Ga,Al)이 도핑된 ZnO를 투명전극으로 가진 Cu(In,Ga)Se2 태양전지에 수분이 미치는 영향)

  • Yang, So Hyun;Bae, Jin A;Song, Yu Jin;Jeon, Chan Wook
    • Current Photovoltaic Research
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    • v.5 no.4
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    • pp.135-139
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    • 2017
  • We fabricated two different transparent conducting oxide thin films of ZnO doped with Ga ($Ga_2O_3$ 0.9 wt%) as well as Al ($Al_2O_3$ 2.1 wt%) (GAZO) and ZnO doped only with Al ($Al_2O_3$ 3 wt%) (AZO). It was investigated how it affects the moisture resistance of the transparent electrode. In addition, $Cu(In,Ga)Se_2$ thin film solar cells with two transparent oxides as front electrodes were fabricated, and the correlation between humidity resistance of transparent electrodes and device performance of solar cells was examined. When both transparent electrodes were exposed to high temperature distilled water, they showed a rapid increase in sheet resistance and a decrease in the fill factor of the solar cell. However, AZO showed a drastic decrease in efficiency at the beginning of exposure, while GAZO showed that the deterioration of efficiency occurred over a long period of time and that the long term moisture resistance of GAZO was better.

RF-magnetron sputtering 방법으로 성장시킨 Ga-doped ZnO 박막의 성장 온도 변화에 따른 영향

  • Kim, Yeong-Lee;U, Chang-Ho;An, Cheol-Hyeon;Bae, Yeong-Suk;Gong, Bo-Hyeon;Kim, Dong-Chan;Jo, Hyeong-Gyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.9-9
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    • 2009
  • 1 wt % Ga-dope ZnO (ZnO:Ga) thin films with n-type semiconducting behavior were grown on c-sapphire substrates by radio frequency magnetron sputtering at various growth temperatures. The room temperature grown ZnO:Ga film showed the faint preferred orientation behavior along the c-axis with small domain size and high density of stacking faults, despite limited surface diffusion of the deposited atoms. The increase in the growth temperature in the range between $300\sim550^{\circ}C$ led to the granular shape of epitaxial ZnO:Ga films due to not enough thermal energy and large lattice mismatch. The growth temperature above $550^{\circ}C$ induced the quite flat surface and the simultaneous improvement of electrical carrier concentration and carrier mobility, $6.3\;\times\;10^{18}/cm^3$ and $27\;cm^2/Vs$, respectively. In addition, the increase in the grain size and the decrease in the dislocation density were observed in the high temperature grown films. The low-temperature photoluminescence of the ZnO:Ga films grown below $450^{\circ}C$ showed the redshift of deep-level emission, which was due to the transition from $Zn_j$ to $O_i$ level.

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4 inch QVGA AMOLED display driven by GaInZnO TFT

  • Kwon, Jang-Yeon;Son, Kyoung-Seok;Jung, Ji-Sim;Kim, Tae-Sang;Ryu, Myung-Kwan;Park, Kyung-Bae;Kim, Jung-Woo;Lee, Young-Gu;Kim, Chang-Jung;Kim, Sun-Il;Park, Young-Soo;Lee, Sang-Yoon;Kim, Jong-Min
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.141-144
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    • 2007
  • We demonstrated 4 inch QVGA AMOLED display driven by GaInZnO TFT. The structure of GaInZnO TFT is back channel etch (BCE) which is conventional structure for a-Si TFT. The electron mobility of GaInZnO TFT is $2.6\;cm^2/Vs$ and Vt is 3.8V. It is thought that GaInZnO TFT could be backplane for AMOLED TV.

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Luminescence Properties of $Dy^{3+}-(or Tm^{3+}-)$ Doped $Ga_2O_3$ and $ZnGa_2O_4$ Phosphors

  • Ryu, Ho-Jin;Park, Hee-Dong
    • The Korean Journal of Ceramics
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    • v.3 no.2
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    • pp.134-138
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    • 1997
  • $Dy^{3+}-(or Tm^{3+}-)$ doped $Ga_2O_3 \;and\; ZnGa_2O_4$ phosphors were prepared using the solid state reaction method to investigate their photoluminescent characteristics. Under 254 nm excitation, $Dy^{3+}-doped Ga2_O_3$ exhibited two emission bands of 460~505nm and 570~600nm. On the other hand, $Dy^{3+}-(or Tm^{3+}-)$ doped $ZnGa_2O_4 $phosphors exhibited a broad-band emission extending from 330 nm to 610 nm, peaking at about 430 nm(or 370 nm). In this study, an emission peak shift of nealy 50 nm towards longer wavelength region was observed with $Dy^{3+}$ doping in the $ZnGa_2O_4 $.

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Enhanced Efficiency of Transmit and Receive Module with Ga Doped MgZnO Semiconductor Device by Growth Thickness

  • Shim, Bo-Hyun;Jo, Hee-Jin;Kim, Dong-Jin;Chae, Jong-Mok
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.1
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    • pp.39-43
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    • 2016
  • The structural, electrical properties of Ga doped MgZnO transparent conductive oxide (TCO) films by ratio-frequency(RF) magnetron sputtering were investigated. Ga doped MgZnO TCO films were deposited on the sapphire substrates at $200^{\circ}C$ varying growth thickness 200 to 600 nm. The optical properties of Ga doped MgZnO TCO films were showed above 85% transmittance from 300 to 1000 nm region. In addition, the current density ($J_{SC}$) of $Cu(In,Ga)Se_2$ (CIGS) solar cells was improved by using the MgZnO:Ga films of 500 nm thickness because of outstanding electrical properties. The $Cu(In,Ga)Se_2$ solar cells with MgZnO:Ga transparent conducing layer yielded an efficiency of 9.8% with current density ($31.8mA/cm^2$), open circuit voltage (540.2 V) and fill factor (62.2) under AM 1.5 illumination.