• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.461-465
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• 2011

An aluminum doped zinc oxide (AZO) film for front contacts of thin film solar cells, in this work, were deposited by r.f. magnetron sputtering, and then etched in diluted hydrochloric acid solution for different times. Effects of surface texturing on the electro-optical properties of AZO films were investigated. Also, to clarify the light trapping of textured AZO film, amorphous silicon thin film solar cells were fabricated on the textured AZO/glass substrate and the performance of solar cells were studied. After texturing, the spectral haze at the visible range of 400 ~750 nm increased substantially with the etching time, without a change in the resistivity. The conversion efficiency of amorphous Si solar cells with textured AZO film as a front electrode was improved by the increase of short-circuit current density ($J_{sc}$), compared to cell with flat AZO films.

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

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.85-89
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• 2018

In this study, functional transparent conducting layers were investigated for Si-based photoelectric applications. Double transparent conductive oxide (TCO) films were deposited on a Si substrate in the sequence of indium tin oxide (ITO) followed by aluminum-doped zinc oxide (AZO). First, we observed that the conductivity and transparency of AZO dominate the overall performance of the double TCO layers. Secondly, the double layered TCO film (consisting of AZO/ITO) deposited by sputtering was compared to a AZO-only film in terms of their optical and electrical properties. We prepared three different AZO films: ITO:3min/AZO:10min, ITO:5min/AZO:7min, and ITO:7min/AZO:4min. The results show that the optical properties (transmittance, absorbance, and reflection) can be controlled by the film composition. This may provide a significant pathway for the manipulation of the optical and electrical properties of photoelectric devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.209-209
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• 2012

High-efficient transparent conductive oxide (TCO) film-embedding Si heterojunction solar cells were fabricated. An additional doping was not applied for heterojunction solar cells due to the spontaneous junction formation between TCO films and an n-type Si substrate. Three different TCO coatings were formed by sputtering method for an Al-doped ZnO (AZO) film, an indium-tin-oxide (ITO) film and double stacks of ITO/AZO films. An improved crystalline ITO film was grown on an AZO template upon hetero-epitaxial growth. This double TCO films-embedding Si heterojunction solar cell provided significantly enhanced efficiency of 9.23% as compared to the single TCO/Si devices. The effective arrangement of TCO films (ITO/AZO) provides benefits of a lower front contact resistance and a smaller band offset to Si leading enhanced photovoltaic performances. This demonstrates a potential scheme of the effective TCO film-embedding heterojunction Si solar cells.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.90-90
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• 2011

Transparent conducting oxide (TCO) films have been intensively utilized in the electric applications, such as, displays, lightings and solar cells due to the good electric conductivity with an excellent transmittance of the visible light. We, herein present an excellent Al-doped ZnO film (AZO), which has been fabricated by co-sputtering method. An as-deposited AZO film had an optical transmittance of 84.78% at 550 nm and a resistivity of $7.8{\times}10^{-3}{\Omega}cm$. A rapid annealing process significantly improved the optical transmittance and electrical resistivity of the AZO film to 99.67% and $1{\times}10^{-3}{\Omega}cm$, respectively. The fabricated AZO film was fabricated for a metal-semiconductor-metal (MSM) structure. The AZO film-embedding MSM device was highly responsive to a UV light.

• 한국재료학회지
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• 제30권6호
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• pp.285-291
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• 2020

Recent advances in technology using ultra-thin noble metal film in oxide/metal/oxide structures have attracted attention because this material is a promising alternative to meet the needs of transparent conduction electrodes (TCE). AZO/Ag/AZO multilayer films are prepared by magnetron sputtering for Cu₂ZnSn(S,Se)₄ (CZTSSe) of kesterite solar cells. It is shown that the electrical and optical properties of the AZO/Ag/AZO multilayer films can be improved by the very low resistivity and surface plasmon effects due to the deposition of different thicknesses of Ag layer between oxide layers fixed at AZO 30 nm. The AZO/Ag/AZO multilayer films of Ag 15 nm show high mobility of 26.4 ㎠/Vs and low resistivity and sheet resistance of 3.58^⁎10^-5 Ωcm and 5.0 Ω/sq. Also, the AZO/Ag (15 nm)/AZO multilayer film shows relatively high transmittance of more than 65 % in the visible region. Through this, we fabricated CZTSSe thin film solar cells with 7.51 % efficiency by improving the short-circuit current density and fill factor to 27.7 mV/㎠ and 62 %, respectively.

• 한국재료학회지
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• 제21권6호
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• pp.341-346
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• 2011

In this study, we inserted a Zn buffer layer into a AZO/p-type a-si:H layer interface in order to lower the contact resistance of the interface. For the Zn layer, the deposition was conducted at 5 nm, 7 nm and 10 nm using the rf-magnetron sputtering method. The results were compared to that of the AZO film to discuss the possibility of the Zn layer being used as a transparent conductive oxide thin film for application in the silicon heterojunction solar cell. We used the rf-magnetron sputtering method to fabricate Al 2 wt.% of Al-doped ZnO (AZO) film as a transparent conductive oxide (TCO). We analyzed the electro-optical properties of the ZnO as well as the interface properties of the AZO/p-type a-Si:H layer. After inserting a buffer layer into the AZO/p-type a-Si:H layers to enhance the interface properties, we measured the contact resistance of the layers using a CTLM (circular transmission line model) pattern, the depth profile of the layers using AES (auger electron spectroscopy), and the changes in the properties of the AZO thin film through heat treatment. We investigated the effects of the interface properties of the AZO/p-type a-Si:H layer on the characteristics of silicon heterojunction solar cells and the way to improve the interface properties. When depositing AZO thin film on a-Si layer, oxygen atoms are diffused from the AZO thin film towards the a-Si layer. Thus, the characteristics of the solar cells deteriorate due to the created oxide film. While a diffusion of Zn occurs toward the a-Si in the case of AZO used as TCO, the diffusion of In occurs toward a-Si in the case of ITO used as TCO.

• 한국전기전자재료학회논문지
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• 제25권7호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.443-443
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• 2012

We fabricated a-IGZO TFT with AZO/Ag/AZO transparent multilayer source/drain contacts by rf magnetron sputtering. Enhanced electrical device performance of a-IGZO TFT with AZO/Ag/AZO multilayer S/D electrodes (W/L = = 400/50 mm) was achieved with a subs-threshold swing of 3.78 V/dec, a minimum off-current of 10-12 A, a threshold voltage of 1.80 V, a field effect mobility of 10.86 cm2/Vs, and an on/off ration of 9x109. It demonstrated the potential application of the AZO/Ag/AZO film as a promising S/D contact material for the fabrication of the high performance TFTs.

• 대한기계학회논문집B
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• 제37권6호
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• pp.577-582
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• 2013

AZO(Aluminium-doped Zinc Oxide)는 기존의 LCD, OLED, 광센서, 유기태양전지 등의 투명전극에 널리 사용되는 ITO(Indium Tin Oxide)를 대체하기 위한 물질로 주목받고 있다. 본 연구에서는 유기태양전지의 투명 전극으로 많이 사용되는 ITO 를 대체하기 위해 원자층 증착(ALD) 공정의 저온 선택적 증착 특성을 이용하여 유연성 폴리머인 PEN 기판상에 AZO 투명전극을 직접 패턴방식으로 제조하고, 그 투명전극의 구조적, 전기적, 광학적 특성을 평가하였다. 전기적, 광학적 특성 결과들로부터 원자층 증작공정의 저온 선택적 증착 특성을 통해 형성된 AZO 투명전극의 유기태양전지로의 적용 가능성을 확인할 수 있었다.