• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.8
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• pp.666-670
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• 2007

Aluminuim doped zinc oxide(ZnO:AL)Films have been prepared on Polyimide(PI) and Coming 7059 glass substrates by r.f. magnetron sputtering method. The structural of the ZnO:Al films were studied in accordance with various deposition R.F power and working pressure by XRD, SEM. And The electrical and optical properties of ZnO:Al films were characterized by Hall effect and UN visible spectrophotometer measurements, ZnO:Al films had were hexagonal wurtzite structure and dominant c-axis orientation. The R.f power and working pressure for optimum condition to fabricate the transparent conductive films using a PI substrate were 2 mTorr and 100W, respectively. The resistivity of the ZnO:Al films prepared under this condition were $9.6{\times}10^{-4}{\Omega}cm$. The optical transmittance of 400nm thick films at 550nm is ${\sim}85 %$.

• The Korean Journal of Ceramics
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• v.7 no.2
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• pp.85-92
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• 2001

Thin films of ZnO and Al doped ZnO were prepared by rf magnetron sputter techniques. When the oxygen fraction in Ar-O$_2$ sputter gas was about 2.0%, the films exhibited the composition of Zn:O=1.05:1. The films prepared at 250 W contain larger grains than the films grown at 100 W. However, high deposition rate seems to deteriorates the crystallinity as well as Al-substitution, resulting in lower concentration of mobile electrons. The Al-doped ZnO films which were deposited at $500^{\circ}C$ show resistance of 1$\times$10$^-2$ Wcm; optical band gap of the films ranges from 3.25 to 3.40 eV. These electrical and optical features are related with microstructural as well as crystalline characteristics of the films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.535-538
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• 2004

Zinc Oxide (ZnO) films have attracted considerable attention for transparent conducting films, because of their high conductivity, good optical transmittance from UV to near IR as well as a low-cost fabrication. To increase the conductivity of ZnO, doping of group III elements (Al, Ga, In and B) has been carried out. Transparent conducting films have been applied for optoelectric devices, the development of the transparent conducting thin films on flexible light-weight substrates are required. In this research, the transparent conducting ZnO thin films doped with Aluminum (Al) on polymer substrates were deposited by the RF magnetron suputtering method, and the structural, optical and electrical properties were investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.319.1-319.1
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• 2016

Recently, the Al-doped ZnO (ZnO:Al) films are intensively used in thin film a-Si solar cell applications due to their high transmittance and good conductivity. The textured ZnO:Al films are used to enhance the light trapping in thin film solar cells. The wet etch process is used to texture ZnO:Al films by dipping in diluted acidic solutions like HCl or HF. During that process the glass substrate could be damaged by the acidic solution and it may be difficult to apply it for the inline mass production process since it has to be done outside the chamber. In this paper we report a new technique to control the surface morphology of RF-sputtered ZnO:Al films. The ZnO:Al films are textured with vaporized HF formed by the mixture of HF and H2SiO3 solution. Even though the surface of textured ZnO:Al films by vapor etching process showed smaller and sharper surface structures compared to that of the films textured by wet etching, the haze value was dramatically improved. We achieved the high haze value of 78% at the wavelength of 540 nm by increasing etching time and HF concentration. The haze value of about 58% was achieved at the wavelength of 800 nm when vapor texturing was used. The ZnO:Al film texture by HCl had haze ratio of about 9.5 % at 800 nm and less than 40 % at 540 nm. In addition to low haze ratio, the texturing by HCl was very difficult to control etching and to keep reproducibility due to its very fast etching speed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1488-1493
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• 2017

Boron-doped ZnO:Al films were deposited by rf magnetron sputtering. The structural and optical property variations of the films with the boron amounts were studied. ZnO nanorods were grown on $SiO_2/Si$ wafers and glass by a hydrothermal method. ~50 nm-thick boron-doped ZnO:Al films were deposited on the substrates as seed layers. The mixed solution of zinc nitrate hexahydrate and hexamethylenetetramine in DI water was used as a precursor for ZnO nanorods. The concentration of zinc nitrate hexahydrate and that of hexamethylenetetramine were 0.05 mol, respectively. ZnO nanorods were grown at $90^{\circ}C$ for 2 hours. X-ray diffraction was conducted to observe the crystallinity of ZnO nanorods. A field emission scanning electron microscope was employed to study the morphology of nanorods. Optical transmittance was measured by a UV-Vis spectrophotometer, and photoluminescence was carried out with 266 nm light. The ZnO nanorods grown on the 0.5 wt% boron-doped ZnO seed layer showed the best crystallinity.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.189-194
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• 1999

The heat treatment effects of the undoped ZnO and Al doped ZnO(AZO) transparent conductive films prepared by rf magnetron sputtering were investigated. The variations of the electrical and optical properties with heat treatment temperature and ambient were studied. The resistivity of the un doped ZnO films heat treated in air and $H_z$ plasma for 1 hour increased rapidly above $200^{\circ}C$ and $300^{\circ}C$, respectively. And that of the ZnO:Al films heat treated in air also increased rapidly above $300^{\circ}C$. On the other hand that of the ZnO:Al films heat treated in $H_z$ plasma was constant regardless of heat treatment temperature. The optical transmittance above 550nm is about 90% for all thin films regardless of impurity doping, the heat treatment temperature and ambient.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.252-252
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• 2009

In this work, the nanocrystalline ZnO/polycrystalline (poly) aluminum nitride (AlN)/Si structure was fabricated for humidity sensor applications based on surface acoustic wave (SAW). In this structure, the ZnO film was used as sensing material layer. These ZnO and AlN(0002) were deposited by so-gel process and a pulse reactive magnetron sputtering, respectively. These experimental results showed that the obtained SAW velocity on AlN film was about 5128 m/s at $h/\lambda$=0.0125 (h and $\lambda$ is thickness and wavelength, respectively). For ZnO sensing layers coated on AlN, films have hexagonal wurtzite structure and nanometer particle size. The crystalline size of ZnO films annealed at 400, 500, and 600 $^{\circ}C$ is 10.2, 29.1, and 38 nm, respectively. Surface of the film exhibits spongy which can adsorb steam in the air. The best quality of the ZnO film was obtained with annealing temperature at 500 $^{\circ}Cis$. The change in frequency response (127.9~127.85 MHz) of the SAW humidity sensor based on ZnO/AlN structure was measured along the change in humidity (41~69%). The structural properties of thin films wereinvestigated by XRD and SEM.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1301-1304
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• 1994

ZnO transparent conducting oxide thin films have been prepared by Pyrosol deposition method. The effect of the Al doping with varying Al/Zn mole ratio and the post-deposition heat treatment on the electrical resistivity and optical transmittance of the prepared films have been investigated. From the experimental results, the ZnO:Al thin films with resistivity as low as $3{\times}10^{-3}{\Omega}cm$ and transmittance as high as 80% can be obtained by Al doping. Also We have found the annealing of the as-deposited ZnO film in vacuum leads to a substantial reduction in resistivity without affecting the optical transmittance and crystallographic orientation. However, the annealing effect of ZnO:Al thin films is smaller than ZnO films with respect to reduction in resistivity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.277-283
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• 2009

In this paper, aluminum doped zinc oxide (ZnO:Al) thin films on plastic substrate such as poly carbonate (PC), polyethylene terephthalate (PET) were prepared by RF magnetron sputtering method for flexible solar cell applications. Effects of the sputter pressure on the structural, electrical and optical properties were investigated. The crystallinity and the degree of the (002) orientation were deteriorated with increasing the sputter pressure. When the sputter pressure was higher, the conductivity of ZnO:Al films was improved because of the high carrier concentration and the Hall mobility. High quality ZnO:Al films with resistivity as low as $1.9{\times}10^{-3}{\Omega}-cm$ and the optical transmittance over 80 % in the visible region have been obtained on PC substrate at 2 mTorr.

• Journal of the Korean Vacuum Society
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• v.22 no.3
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• pp.119-125
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• 2013

In this study, we studied the properties of ZnO(Al) and ZnO(AlGa) thin film according to film thickness deposited on SLG by In-line magnetron sputtering system. XRD, FESEM, 4-point probe, Hall measurement system and UV/Vis-NIR spectrophotometer were employed to analyze the properties of ZnO(Al) and ZnO(AlGa) thin film. The all films exhibited (002) preferential orientation with clear peak shape and high intensity. The carrier concentration and Hall mobility of ZnO(Al) and ZnO(AlGa) thin film were improved with increasing thickness. The resistivity of both films decreased when the film thickness was raised from 500 nm to 1,450 nm. And then relatively the resistivity of ZnO(AlGa) film was lower than that of ZnO(Al) film. The transmittance of the films decreased with increasing film thickness but all films exhibited optical transmittances of over 83.3% in the visible region.