• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.543-551
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• 2012

In this study, transparent conducting Al-doped Zinc Oxide (AZO) films with a thickness of 150 nm were prepared on corning glass substrate by the RF magnetron sputtering with using a Al-doped zinc oxide (AZO), ($Al_2O_3$: 2 wt%) target at room temperature. This study investigated the effect of rapid thermal annealing temperature and oxygen ambient on structural, electrical and optical properties of Al-doped zinc oxide (AZO) thin films. The films were annealed at temperatures ranging from 400 to $700^{\circ}C$ by using Rapid thermal equipment in oxygen ambient. The effect of RTA treatment on the structural properties were studied by x-ray diffraction and atomic force microscopy. It is observed that the Al-doped zinc oxide (AZO) thin film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas reveals the strongest XRD emission intensity and narrowest full width at half maximum among the temperature studied. The enhanced UV emission from the film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas is attributed to the improved crystalline quality of Al-doped zinc oxide (AZO) thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size.

• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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• pp.279-284
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• 2010

This study has been carried out to determine the optimal process conditions of $AZO:H_2$ thin films for the maximization of the transmittance of a blue GaN light-emitting diode (LED) with a wavelength of 470 nm. The Al-doped zinc oxide $(AZO):H_2$ thin films were deposited on a sapphire substrate by radio-frequency magnetron sputtering system with varying substrate temperatures, working pressures and annealing temperatures temperature, working pressure and annealing imposed on a AZO (2wt% $Al_2O_3$) ceramic target. The effect of these variables was investigated in order to improve the light extraction efficiency of the LED. As a result, the (002)-oriented peak was found in all the $AZO:H_2$ thin films. The lowest resistivity and the best transmittance at a wavelength of 470 nm was found to be $4.774\;{\times}\;10^{-4}\;{\Omega}cm$ and 92% at a substrate temperature of $500^{\circ}C$, working pressure of 7 mTorr and annealing temperature of $400^{\circ}C$. The transmittance of the $AZO:H_2$ thin film for the Blue GaN LED was improved by approximately 13% relative to that of a ITO thin film (T = 79%).

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.27-31
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• 2017

AZO/Ag/AZO multi-layer films deposited on glass substrate by RF magnetron sputtering and thermal evaporator have a much better electrical properties than Al-doped ZnO thin films. The multi-layer structure consisted of three layers, AZO/Ag/AZO, the electrical and optical properties of AZO/Ag/AZO were changed mainly by thickness of Ag layers. The optimum thickness of Ag layers was determined to be $90{\AA}$ for high optical transmittance and good electrical conductivity. The Ag layers thickness $90{\AA}$ is an optical transmittance greater than 80% of visible light and the obtained multilayer thin film with the low resistivity of $8.05{\times}10-3{\Omega}cm$ and the low sheet resistance $5.331{\Omega}/sq$. Applying to TCO and Solar electrode will improve efficiency.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.401-401
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• 2011

In this work, we deposited Al2O3doped ZnO (AZO) thin films by direct current (DC) magnetron sputtering method with a $40^{\circ}$ tilted target, for application in the front layer of thin film solar cell. Wet chemical etching behavior of AZO films was also investigated. In order to optimize textured AZO films, oxalic acid ($C_2H_2O_4$)has been used as wet etchant of AZO film. In this experiment we used 0.001% concentration of oxalic acid various etching time, that showed an anisotropy in etching texture of AZO films. Electrical resistivity, Hall mobility and carrier concentration measurements are performed by using the Hall measurement, that are $6{\times}10^{-4}{\Omega}cm$, $20{\sim}25cm^2/V-s$ and $4{\sim}6{\times}10^{20}$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.165-165
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• 2010

AZO:H films were prepared by RF magnetron sputtering system with a AZO (2wt% $Al_2O_3$) ceramic target at a temperature of $150^{\circ}C$. The annealing treatments were carried out in hydrogen ambient for 1hr at a temperature of $400^{\circ}C$. The AZO:H films were etched with 1 % HCl. The influence of the properties of AZO:H films deposited in various working pressures is investigated. As a result, the AZO:H film deposited in 4mTorr showed excellent electrical property of $\rho=5.036{\times}10^{-4}{\Omega}cm$ and strongly oriented (002) peak. The transmittance in the wavelength of 450nm was above 80%. It can be used as front electrode for increasing efficiency of GaN LED.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.5
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• pp.1-7
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• 2007

AZO thin films have been fabricated on quartz substrate with various Al doping concentrations and annealing temperatures by sol-gel method. The bset condition of (002) orientation and smooth surface (rms = 1.082 nm) is obtained for the AZO thin film doped with 1 mol % Al and annealed at 550 $^{\circ}C$. The optical transmittance of AZO thin films is higher than 80 % in the visible region. We observe that the energy band gap extends with increasing the Al doping concentration. This phenomenon is due to the Burstein-Moss effect. Through the measurement of Hall effect, it is observed that the AZO thin film has larger carrier concentration and smaller electrical resistivity than the pure ZnO thin film. However, the AZO thin film shows the decrease of carrier concentration and the increase of resistivity with the increase of Al concentration, that is due to the segregation of Al at grain boundaries. The maximum carrier concentration of $1.80{\times}10^{19}\;cm^{-3}$ and the minimum resistivity of 0.84 ${\Omega}cm$ are obtained for the AZO thin film doped with 1 mol % Al and annealed at 550 $^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1859-1861
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• 2005

The ZnO:Al thin films were prepared on glass by Facing Target Sputtering (FTS) system. We investigated electrical, optical, and structural properties of AZO thin film with sputtering current $0.1[A]{\sim}0.6[A]$. We obtained the lowest resistivity $2.3{\times}10^{-4}[{\Omega}-cm]$ at sputtering current 0.6[A] from the 4-point probe and the strong (002) peak at sputtering current 0.3[A] from the X-ray Diffractometer (XRD ). The optical transmittance of AZO thin films show a very high transmittance of $80{\sim}95%$ in the visible range and exhibit the absorption edge of about 350nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.39-40
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• 2006

We prepared ZnO:Al (AZO) thin films on polycarbonate (Pc) and polyethersulfon (PES). Because the polymer substrate has weak thermal resistance. The AZO thin films were deposited at room temperature by facing targets sputtering (FTS) method In the work, AZO thin films were deposited with different thickness in 1mTorr and $O_2$ gas flow rate 0.05. The electrical, optical and crystallographic properties were measured From the results, the resistivity of $7.3{\times}10^{-4}{\Omega}cm$ and transmittance of over 80% in visible range were obtained.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.50.1-50.1
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• 2009

Transparent conductive oxides (TCOs) play an important role in thin-film solar cells in terms of low cost and performance improvement. Al-doped ZnO (AZO) is a very promising material for thin-film solar cellfabrication because of the wide availability of its constituent raw materials and its low cost. In this study, AZO films were prepared by low pressurechemical vapor deposition (LPCVD) using trimethylaluminum (TMA), diethylzinc(DEZ), and water vapor. In order to improve the absorbance of light, atypical surface texturing method is wet etching of front electrode using chemical solution. Alternatively, LPCVD can create a rough surface during deposition. This "self-texturing" is a very useful technique, which can eliminate additional chemical texturing process. The introduction of a TMA doping source has a strong influence on resistivity and the diffusion of light in a wide wavelength range.The haze factor of AZO up to a value of 43 % at 600 nm was achieved without an additional surface texturing process by simple TMA doping. The use of AZO TCO resulted in energy conversion efficiencies of 7.7 % when it was applied to thep-i-n a-Si:H thin film solar cell, which was comparable to commercially available fluorine doped tin oxide ($SnO_2$:F).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.172-175
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• 2003

ZnO:Al thin film for application to FBAR's bottom electrode using ZnO piezoelectric thin film were prepared by FTS, in order to improve the crystallographic properties of ZnO thin films because the ZnO:Al thin film and ZnO thin films structure is equal each other. So we prepared the ZnO:Al thin film with oxygen gas flow rate. Thickness and c-axis preferred orientation and electric properties of ZnO:Al bottom electrode were evaluated by $\alpha$-step, XRD and 4-point probe..