• 한국진공학회지
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• 제19권3호
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• pp.206-210
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• 2010

RF 마그네트론 스퍼터링법을 이용하여 Al 도핑된 ZnO 박막을 Ar 유량에 따라 증착하고 박막의 다양한 특성을 연구하였다. ZnO 박막의 Ar 유량 변화를 통해 고품질 박막을 증착할 수 있었고 Al 도핑된 ZnO 박막에 대한 Ar 유량의 영향을 확인하였다. 모든 Al 도핑된 ZnO에서 80% 이상의 좋은 투과도를 보였다. Hall 측정과 X-ray photoelectron spectrometer 측정 결과, 비저항이 가장 작은 60 sccm에서 가장 작은 Al 도핑 농도를 보였다. Ar 유량에 따른 Al 도핑된 ZnO 박막에서의 전기적인 특성은 Al 도핑 농도보다 산소 공공에 의해 더 영향을 받음을 확인하였다.

• 한국진공학회지
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• 제19권1호
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• pp.58-65
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• 2010

먼저 RF 마그네트론 스퍼터링법을 이용하여 사파이어 기판 위에 AlN 박막을 증착하였다. AlN 공급원으로는 분말소결된 AlN 타겟을 적용하였다. 플라즈마 파워를 50에서 110 W로 증가시켰을 때 AlN 층의 두께는 선형적으로 증가하였다. 그러나 동작압력을 3에서 10 mTorr로 증가시켰을 때는 동작기체인 아르곤 양이 증가함에 따라 AlN 타겟으로부터 스퍼터링되어 나온 AlN 입자들의 평균자유행정의 거리가 감소하기 때문에 AlN 층의 두께는 약간 감소하였다. 질소 기체를 아르곤과 섞어주었을 때는 질소의 낮은 스퍼터링 효율에 의해서 AlN의 두께는 크게 감소하였다. 다음으로는 ZnO 형판 위에 AlN를 증착하였다. 그러나 700도 이상의 열처리에 의해서 AlN와 ZnO의 계면이 약간 분리되어 계면의 열적 안정성이 낮다는 결과를 얻었다. 게다가 스퍼터링으로 증착한 AlN 박막의 나쁜 결정성으로 인하여 700도에서 MOCVD의 반응기 기체인 수소와 암모니아에 의해서 AlN 밑의 ZnO 층이 분해되는 현상도 관찰하였다. 그리고 900도 이상에서는 ZnO가 완전히 분해되어 AlN 박막이 완전히 분리되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.175-175
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• 2008

투명전극으로 사용되고 있는 Indium tin oxide (ITO) 박막은 전기적 전도도와 기판과의 접확성, 화학적 안정성, 광투과율 등의 특성과 함께 우수한 전기 광학적 거동을 보이고 있다. 그러나 ITO는 고가의 재료이기 때문에 대체 투명전극으로 Al을 도핑한 ZnO 박막의 연구가 활발히 진행되고 있다. ZnO:Al 박막은 chemical vapor deposition, reactive magnetron sputtering, electron-beam evaporation, pulsed laser deposition 등의 당양한 방법을 이용하여 증착하였다. 그러나 최근 낮은 온도에서 대면적의 균일성과 우수한 특성 때문에 atomic layer depositon (ALD) 방법을 이용하여 많은 연구가 진행되고 있으며, 이런 투명전극은 태양전지를 위해 연구되어지고 있다. 따라서 본 연구에서는 ALD 방법으로 Al의 도핑 양을 조절하여, ZnO:Al 박막을 제조하여 그 특성을 평가하고, 또한 ZnO TFT를 제작하여 발표하고자 한다. ZnO와 ZnO:Al 박막은 실리콘과 유리 기판 위에 ALD (Lucida-D200, NCD Technology) 장치로 증착하였다. DEZn, TMA, $H_2O$는 ZnO와 ZnO:Al 박막을 증착하기 위한 전구체와 반응가스로 사용하였다. 증착된 박막은 XRD와 HRTEM을 이용하여 결정구조와 미세구조를 분석하였다. AFM과 4-point probe를 이용하여 증착된 박막의 표면 거칠기와 면저항을 관찰하였다. semiconductor parameter 분석기를 이용하여 제작된 ZnO TFT를 평가하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.235-236
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• 2008

Wet etched ZnO:Al films for thin film solar cells were prepared by Facing Target sputtering(FTS) method. Wet etching has been used to produce a rough TCO surface that enables light trapping in the absorber. The ZnO:Al films for thin film solar cells were etched by HCl 0.5%. The etching performance of ZnO:Al films can be tuned by changing etching time. The etched ZnO:Al films compared to a smooth ZnO:Al thin film structure. From the results, the lowest resistivity of deposited films was $5.67\times10^{-4}$ [$\Omega$-cm] and the transmittance of all ZnO:Al thin films were over 80% in visible range.

• Current Photovoltaic Research
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• 제3권1호
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• pp.32-38
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• 2015

CIGS solar cell consisted of various films. In this research, we investigated electrode materials in $Cu(In,Ga)Se_2$ (CIGS) cells, including Al-doped ZnO (ZnO:Al), intrinsic ZnO (i-ZnO), and Al films. The sputtered ZnO:Al film with a sputtering power at 200W showed the lowest series resistance and highest cell efficiency. The electrical resistivity of the 200-W sputtered ZnO:Al film was $5.2{\times}10^{-4}{\Omega}{\cdot}cm$ by the rapid thermal annealing at $200^{\circ}C$ for 1 min. The electrical resistivity of i-ZnO was not measurable due to its high resistance. But the optical transmittance was highest with less oxygen supply and high efficiency cell was achieved with $O_2/(Ar+O_2)$ ratio was 1% due to the increase of short-circuit current. No significant change in the cell performance by inserting a Ni layer between Al and ZnO:Al films was observed.

• 한국재료학회지
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• 제14권5호
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• pp.328-333
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• 2004

Transparent ZnO:Al conductor films for the optoelectronic devices were deposited by using the capacitively coupled DC magnetron sputtering method. The effect of Al doping concentration and discharge power on the electrical and optical properties of the films was studied. The film resistivity of $8.5${\times}$10^{-4}$ $\Omega$-cm was obtained at the discharge power of 40 W with the ZnO target doped with 2 wt% $Al_2$$_O3$. The transmittance of the 840 nm thick film was 91.7% in the visible waves. Increasing doping concentration of 3 wt% $Al_2$$O_3$ in ZnO target results in significant decrease of film resistivity, which may be due to the formation of $Al_2$$O_3$ particles in the as-deposited ZnO:Al film and the reduced ZnO grain sizes. Increasing DC power from 40 to 60 W increases deposition rate by more than 50%, but can induce high defect density in the film, resulting in higher film resistivity.

• 한국재료학회지
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• 제16권7호
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• pp.449-454
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• 2006

Al-doped zinc oxide (ZnO:Al) films for transparent electrodes in thin film solar cells were deposited on glass substrates at a low temperature of $200^{\circ}C$ by rf magnetron sputtering. The transmittance of the ZnO:Al films in the visible range was 87%. The lowest resistivity of the ZnO:Al films was about $5.8{\times}10^{-4}{\Omega}$ cm at the Al content of 2.5 wt%. After deposition, the surface of ZnO:Al films were etched in dilute HCl (0.5%) for the investigation of the change in the electrical properties and the surface morphology due to etching.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.207-212
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• 1998

By comparison of the experimental results in two systems of ZnO varistors, it's appear that Sb2O3 is the indispensable element for twining in ZnO varistors and the Zn7Sb2O12 spinel acts as the nucleus to form twins. Al2O3 is not the origin of twining in ZnO varistor, but it was found that Al2O3 could strengthen the twining and form a deformation twining by ZnAl2O4 dragging and pinning effect. The inhibition ratios of grain and nonuniformity of two systems ZnO varistors increase with the increase of Al2O3 content. The twins affect the inhibition of grain growth, the mechanism could be explained follow as: twins increase the mobility viscosity of ZrO grain and grain boundary, and drag ZrO grain and liquid grain boundary during the sintering, then the grain growth is inhibited and the microstructure becomes more uniform.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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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.

• 한국재료학회지
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• 제30권8호
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• pp.399-405
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• 2020

In the present investigation we show the effect of Al doping on the length, size, shape, morphology, and sensing property of ZnO nanorods. Effect of Al doping ultimately leads to tuning of electrical and optical properties of ZnO nanorods. Undoped and Al-doped well aligned ZnO nanorods are grown on sputtered ZnO/SiO₂/Si (100) pre-grown seed layer substrates by hydrothermal method. The molar ratio of dopant (aluminium nitrate) in the solution, [Al/Zn], is varied from 0.1 % to 3 %. To extract structural and microstructural information we employ field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods show preferred orientation of ZnO <0001> and are well aligned vertically. The effects of Al doping on the electrical and optical properties are observed by Hall measurement and photoluminescence spectroscopy, respectively, at room temperature. We observe that the diameter and resistivity of the nanorods reach their lowest levels, the carrier concentration becomes high, and emission peak tends to approach the band edge emission of ZnO around 0.5% of Al doping. Sensing behavior of the grown ZnO nanorod samples is tested for H₂ gas. The 0.5 mol% Al-doped sample shows highest sensitivity values of ~ 60 % at 250 ℃ and ~ 50 % at 220 ℃.