• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.256-256
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• 2008

We report epitaxial growth of ZnO thin films on (100) single-crystalline $LaAlO_3$ (LAO) substrates using pulsed laser deposition (PLD) at different substrate temperatures (400~$800^{\circ}C$). The structural and electrical properties of the films have been investigated by means of X-ray diffraction (XRD), atomic force microscope (AFM), transmission line method (TLM). The poly-crystalline of $\alpha$- and c-axis oriented ZnO film was formed at lower deposition temperature ($T_s$) of $400^{\circ}C$. At higher $T_s$, however, the films exhibit single-crystalline of $\alpha$-axis orientation represented by ZnO[$\bar{1}11$ || LAO <001>. The electrical properties of ZnO thin films depend upon their crystalline orientation, showing lower electrical resistivity values for $\alpha$-axis oriented ZnO films.

• 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.

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.318-322
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• 2009

In this paper, to establish growth technology of ZnO:Al thin films at low temperature applied to photoelectronic devices, ZnO:Al were prepared by RF magnetron sputtering on glass substrate at room temperature using different RF power with subsequent annealing process at different temperature in $H_2$ ambient. The resistivity of hydrogen-annealed ZnO:Al thin film at temperature of $300^{\circ}C$ was reduced to $8.32{\times}10^{-4}{\Omega}cm$ from $9.44{\times}10^{-4}{\Omega}cm$ which was optimal value for as-grown films. X-ray photoelectron spectroscopy(XPS) revealed that improved electrical properties are ascribed to desorption of the negatively charged oxygen species from the grain boundary surfaces by the hydrogen annealing process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.442-443
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• 2007

Al-N co-doped ZnO films were fabricated on n-Si (100) and homo-buffer layers in the mixture of oxygen and nitrogen at $450^{\circ}C$ by magnetron sputtering. Target was ZnO ceramic mixed with $2wt%Al_2O_3$. XRD spectra show that as-grown and $600^{\circ}C$ annealed films are prolonged along crystal c-axis. However they are not prolonged in (001) plane vertical to c-axix. The films annealed at $800^{\circ}C$ are not prolonged in any directions. Codoping makes ZnO films unidirectional variation. XPS show that Al content hardly varies and N escapes with increasing annealing temperature from $600^{\circ}C\;to\;800^{\circ}C$. The electric properties of as-grown films were tested by Hall Effect with Van der Pauw configuration show some of them to be p-type conduction.

• 한국세라믹학회지
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• 제32권7호
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• pp.799-808
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• 1995

Transparent conductive films of aluminium doped zinc oxide (AZO) have been prepared by using the DC magnetron sputtering with the ZnO : Al (Al2O3 2 wt%) oxide target oriented to c-axis. Electrical and optical properties depended upon the O2/Ar gas ratio. The optical transmittance and sheet resistance of the AZO coated glass was 60~65% and 75Ω/$\square$, respectively at the O2/Ar gas ratio of 0. With the increase of the oxygen partial pressure to 2.0$\times$10-2, they were increased to the values of 81% and 1kΩ/$\square$, respectively. The films with the resistivities of 1.2~1.4$\times$10-3 Ω.cm, mobilities of 11~13 $\textrm{cm}^2$/V.sec and carrier concentrations of 3.5$\times$1020~4.0$\times$1020/㎤ were produced at the optimum O2/Ar gas ratio, which was 0.5$\times$10-2~1.0$\times$10-2. According to XRD analysis, the films have only one peak corresponding to the (002) plane, which indicates that there is a strong preferred orientation of the films. The grain size of ZnO films were calculated to 200~320 $\AA$, which was increased with the O2/Ar gas ratio and Ar gas flowrate.

• 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.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.789-794
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• 2008

Zinc oxide (ZnO) has been widely studied for its practical applications such as transparent conduction electrodes for flat panel displays and solar cells. Especially, ZnO films show good chemical stability against hydrogen plasma, absence of toxicity, abundance in nature, and then suitable for photovoltaic applications. However, the fabrication process of thin film solar cells require a high substrate temperature and/or post heat treatment. Therefore, the layers have to withstand high temperatures, requiring an excellent stability without degrading their electronic and optical properties. In this paper, we investigated the stability of zinc oxide (ZnO) films doped with aluminum and hydrogen. Doped ZnO films were prepared by r.f. magnetron sputter and followed by heat treatment at different temperatures and for various times.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.857-860
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• 2003

Tin doped indium oxide(ITO) and Al doped zinc oxide(ZnO:Al) films, which are widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. The electrical and optical properties of both the ITO and ZnO:Al thin films were investigated as functions of substrate temperature, working gas pressure and deposition time. ITO and ZnO:Al films with the the present experimental conditions of temperature and pressure showed resistivity of $2.36{\times}10^{-4}{\Omega}-cm,\;9.42{\times}10^{-4}{\Omega}-cm$ and transmittance of 86.28%, 90.88% in the wavelength range of the visible spectrum, respectively.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.923-929
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• 2006

Single crystalline ZnO films were successfully grown on R-plane sapphire substrates by plasma-assisted molecular beam epitaxy. Epitaxial relationship between the ZnO film and the R-plane sapphire was determined to be $[-1101]Al_2O_3{\parallel}[0001]ZnO,\;[11-20]Al_2O_2{\parallel}[-1100]ZnO$ based on the in-situ reflection high-energy electron diffraction analysis and confirmed again by high-resolution X-ray diffraction measurements. Grown (11-20) ZnO films surface showed mound-like morphology along the <0001>ZnO direction and the RMS roughness was about 4 nm for $2{\mu}m{\times}2{\mu}m$ area.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.140-142
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• 2003

ZnO thin films are demanded for device applications, so ZnO buffer layer was used to improve for good properties of ZnO thin film. In this study, the structural, electrical and optical properties of ZnO thin films deposited with various buffer thickness was investigated by X-ray diffraction (XRD), Hall measurements, Photoluminescence(PL). ZnO buffer layer and ZnO thin films on sapphire($Al_{2}O_{3}$) substrate have been deposited $200^{\circ}C$ and $400^{\circ}C$ respectively by pulsed laser deposition. It is observed the variety of lattice constant of ZnO thin film by (101) peak position shift with various buffer thickness. It is founded that ZnO thin film with buffer thickness of 20 nm was larger resistivity of 200 factor and UV/visible of 2.5 factor than that of ZnO thin films without buffer layer. ZnO thin films with buffer thickness of 20 nm have shown the most properties.