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

• 한국정보통신학회논문지
• /
• 제14권1호
• /
• pp.191-196
• /
• 2010

본 연구에서는 타겟 제작에 드는 비용을 줄이고, 타겟 이용의 효율성을 높이기 위해 기존의 소결된 세라믹 타겟 대신 분말 타겟으로 사용하여 알루미늄 도핑된 산화아연(Aluminum doped zinc oxde; AZO)박막을 마그네트론 스퍼터법에 의해 제조하고, 스퍼터 압력에 따른 박막 물성을 조사하였다. 유리 기판에 증착된 AZO 박막은 타깃 종류 및 스퍼터 압력에 관계없이 기판에 수직한 c-축 방향으로 우선 성장방위를 갖는 hexagonal 구조로 성장되었다. 스퍼터 압력이 증가함에 따라 이 면 방향으로의 결정성장이 촉진되었다. AZO 박막의 전기적, 광학적 특성은 스퍼터 압력 증가에 따라 향상되었으며, 15 mTorr에서 $6.5{\times}10^{-1}\;{\Omega}-cm$의 최소의 비저항 값을 나타내었다.

• 한국산학기술학회논문지
• /
• 제16권2호
• /
• pp.1555-1562
• /
• 2015

금속 산화물 반도체는 독특한 전기 광학적 특성, 높은 표면적 등으로 인해 태양전지, 센서, 광소자 및 디스플레이 등 여러 분야에 걸쳐 응용되고 있다. 금속 산화물 가운데 우수한 물리 화학적 특성을 가지는 산화아연은 3.37 eV의 넓은 밴드갭 에너지와 60 meV의 큰 엑시톤 결합에너지를 갖는 n-형 반도체로서 산화아연에 양이온을 도핑하여 전기 광학적 특성을 보완하는 연구가 진행되고 있다. 본 연구는 알루미늄이 도핑 된 산화아연을 마이크로파 수열합성법으로 합성하였다. 전구체의 종류와 몰 비 등의 반응 변수를 조절하여 최적의 결정형상과 광학적 특성을 갖는 산화아연을 합성하였으며, 알루미늄을 도핑하여 광학적 특성 변화를 시도하였다. 합성된 입자는 SEM, XRD, PL, UV-Vis 분광기 및 EDS 등의 기기분석을 통해 광학적, 물리 화학적 특성을 확인하였다.

• 한국전기전자재료학회논문지
• /
• 제21권9호
• /
• pp.863-867
• /
• 2008

In this paper, to increase the light current efficiency of photodiode, we fabricated aluminum-doped zinc oxide(AZO) thin films by RF magnetron sputtering. AZO thin films were deposited at low temperature of 100 $^{\circ}C$ and different RF powers of 50, 100, 150 and 200 W due to selective process technology. Then the AZO thin films were annealed at 400 $^{\circ}C$ for 1 hr in vacuum ambient to increase crystalline. The lowest resistivity of 1.35 ${\times}$ $10^{-3}$ ${\Omega}cm$ and a high transmittance over 90 % were obtained under the conditions of 3 mTorr, 100 'c and 150 W. The optimized AZO thin films were deposited as anti-reflection coating on PN junction of silicon photodiode. It was confirmed by the result of $V_r-I_{ph}$ curve that the efficiency of photodiode with AZO thin film was enhanced 17 % more than commercial photodiode.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.60-61
• /
• 2007

IAZO (indium aluminium zinc oxide) anode films were co-sputtered on glass substrate using a dual target DC magnetron sputtering system. For preparation of IATO films, at constant DC power of IZO (indium zinc oxide) target of 100 W, the DC power of AZO (Aluminum zinc oxide) target was varied from 0 to 100 W. To analyze electrical and optical properties of IAZO anode, Hall measurement examination and UV/V is spectrometer were performed, respectively. In addition, structure of IAZO anode film was examined by X-ray diffraction (XRD) method. Surface smoothness was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). From co-sputtered IAZO anode, good conductivity($2.32{\times}10^{-4}{\Omega}.cm$) and high transparency(approximately 80%) in the visible range were obtained even at low temperature deposition. Finally, J-V-L characteristics of phosphorescent OLED with IAZO anode were studied by Keithley 2400 and compared with phosphorescent OLED with conventional ITO anode.

• Bulletin of the Korean Chemical Society
• /
• 제33권4호
• /
• pp.1235-1241
• /
• 2012

Aluminium (Al)-doped zinc oxide (AZO) thin films with different Al concentrations were prepared by the solgel spin-coating method. Optical parameters such as the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity were studied in order to investigate the effects of the Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at infinite wavelength of the AZO thin films were found to be affected by Al incorporation. The optical conductivity of the AZO thin films also increases with increasing photon energy.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.535-538
• /
• 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.

• 한국재료학회지
• /
• 제20권7호
• /
• pp.351-355
• /
• 2010

Transparent conducting aluminum-doped ZnO thin films were deposited using a sol-gel process. In this study, the important deposition parameters were investigated thoroughly to determine the appropriate procedures to grow large area thin films with low resistivity and high transparency at low cost for device applications. The doping concentration of aluminum was adjusted in a range from 1 to 4 mol% by controlling the precursor concentration. The annealing temperatures for the pre-heat treatment and post-heat treatment was $250^{\circ}C$ and 400-$600^{\circ}C$, respectively. The SEM images show that Al doped and undoped ZnO films were quite uniform and compact. The XRD pattern shows that the Al doped ZnO film has poorer crystallinity than the undoped films. The crystal quality of Al doped ZnO films was improved with an increase of the annealing temperature to $600^{\circ}C$. Although the structure of the aluminum doped ZnO films did not have a preferred orientation along the (002) plane, these films had high transmittance (> 87%) in the visible region. The absorption edge was observed at approximately 370 nm, and the absorption wavelength showed a blue-shift with increasing doping concentration. The ZnO films annealed at $500^{\circ}C$ showed the lowest resistivity at 1 mol% Al doping.

• 한국전기전자재료학회논문지
• /
• 제28권3호
• /
• pp.185-190
• /
• 2015

In this study, we fabricated the indium gallium zinc oxide (IGZO), zinc oxide (ZnO), aluminum zinc oxide (AZO). oxide and silver are deposited by magnetron sputtering and thermal evaporator, respectively transparency and energy bandgap were changed by the thickness of silver layer. To fabricate metal oxide metal (OMO) structure, IGZO sputtered on a corning 1,737 glass substrate was used as bottom oxide material and then silver was evaporated on the IGZO layer, finally IGZO was sputtered on the silver layer we get the final OMO structure. The radio-frequency power of the target was fixed at 30 W. The chamber pressure was set to $6.0{\times}10^{-3}$ Torr, and the gas ratio of Ar was fixed at 25 sccm. The silver thickness are varied from 3 to 15 nm. The OMO thin films was analyzed using XRD. XRD shows broad peak which clearly indicates amorphous phase. ZnO, AZO, OMO show the peak [002] direction at $34^{\circ}$. This indicate that ZnO, AZO OMO structure show the crystalline peak. Average transmittance of visible region was over 75%, while that of infrared region was under 20%. Energy band gap of OMO layer was increased with increasing thickness of Ag layer. As a result total transmittance was decreased.

• Transactions on Electrical and Electronic Materials
• /
• 제15권4호
• /
• pp.207-212
• /
• 2014

Aluminum-doped zinc oxide (AZO) films were deposited on SiOC/Si wafer by an RF-magnetron sputtering system, by varying the deposition parameters of radio frequency power from 50 to 200 W. To assess the correlation of the optical properties between the substrate and AZO thin film, photoluminescence was measured, and the origin of deep level emission of AZO thin films grown on SiOC/Si wafer was studied. AZO formed on SiOC/Si substrates exhibited ultraviolet emission due to exciton recombination, and the visible emission was associated with intrinsic and extrinsic defects. For the AZO thin film deposited on SiOC at low RF-power, the deep level emission near the UV region is attributed to an increase of the variations of defects related to the AZO and SiOC layers. The applied RF-power influenced an energy gap of localized trap state produced from the defects, and the gap increased at low RF power due to the formation of new defects across the AZO layer caused by lattice mismatch of the AZO and SiOC films. The optical properties of AZO films on amorphous SiOC compared with those of AZO film on Si were considerably improved by reducing the roughness of the surface with low surface ionization energy, and by solving the problem of structural mismatch with the AZO film and Si wafer.