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Han-ki Kim - One of the best experts on this subject based on the ideXlab platform.
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Transparent Electrode Technologies for Organic Solar Cells and Perovskite Solar Cells
ECS Meeting Abstracts, 2020Co-Authors: Han-ki KimAbstract:The importance of transparent electrode technology for solar cells and perovskite solar cells will be introduced. First, we introduce the roll-to-roll sputtering technique and multilayer electrode for flexible solar cells. We fabricated flexible inverted solar cell (IOSC) modules (10 cm× 10 cm) on roll-to-roll (RTR) sputtered ITO/Ag/ITO multilayer cathodes. By using a pilot-scale RTR sputtering system equipped with mid-range frequency power for dual ITO targets and direct current power for the Ag target, we were able to continuously deposit a high-quality ITO/Ag/ITO multilayer on PET substrate with a width of 700 mm and length of 20,000 mm as a function of Ag thickness. To optimize the electrical and optical properties of the ITO/Ag/ITO multilayer, the thickness of Ag layer was varied by controlling of the DC power applied on Ag targets during the RTR sputtering process. At the Ag thickness of 12 nm, the ITO/Ag/ITO multilayer had a very low sheet resistance of 3.03 Ohm/square and high transmittance of 88.17%, which are better values than those of amorphous ITO film. Various bending test results showed that the high failure strain of the Ag inter layer led to good flexibility of the multilayer films. A strip-type ITO/Ag/ITO cathode was successfully patterned using a RTR wet etching process. Successful operation of flexible IOSC modules on RTR sputtered ITO/Ag/ITO cathodes indicate that the RTR sputtering technique is a promising coating process for fabrication of high-quality transparent and flexible cathodes and can advance the commercialization of cost-efficient flexible IOSCs. Second, we fabricated high-performance flexible CH3NH3PbI3 (MAPbI3) perovskite solar cells with a power conversion efficiency of 16.8% on transparent and flexible ITO electrode prepared by specially designed ion plating system. The ion plated ITO films on PET substrate showed a lower sheet resistance and higher optical transmittance than conventional sputtered ITO films because the high-energy input into a growing ITO film led to densification of the growing film during ion plating process. At optimal coating condition, the ion-plated ITO film with a thickness of 100 nm showed a sheet resistance of 15.75 Ohm/square and an optical transmittance of 84%, which are better than those of sputtered ITO film. Outer and inner bending tests demonstrated that the mechanical flexibility of the ion plated ITO film was superior to that of the conventional sputtered ITO film due to better adhesion between ion plated ITO and PET substrate. Flexible perovskite solar cells with the structure of Au/PTAA/MAPbI3/ZnO/ITO/PET showed a higher power conversion efficiency of 16.8% than sputtered ITO-based flexible perovskite solar cells (15.4%) due to lower sheet resistance and higher optical transmittance. Finally, we introduce a linear facing target sputtering technique to realize semi-transparent perovskite solar cells. By effective confinement of high density Plasma between ITO targets, we can deposit Plasma Damage free IZTO electrode on layer. This indicates that linear facing target sputtering is a promising Plasma Damage free sputtering technique to deposit transparent electrode on perovskite active layer for high efficient semi-transparent perovskite solar cells.
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the effects of thickness on the electrical optical structural and morphological properties of al and ga co doped zno films grown by linear facing target sputtering
Vacuum, 2014Co-Authors: Ki-won Seo, Hyun-su Shin, Ju-hyun Lee, Kwonbum Chung, Han-ki KimAbstract:We investigated the effects of thickness on the electrical, optical, structural, and morphological properties of Al and Ga co-doped ZnO films (AGZO) grown by linear facing target sputtering (LFTS) for use as a transparent contact layer (TCL) in GaN-light emitting diodes (LEDs). Below a critical thickness of 200 nm, the resistivity and optical transmittance of the AGZO films were significantly affected by the thickness of the AGZO films. However, above a thickness of 200 nm, the AGZO films had similar resistivities and optical transmittances due to the stable columnar structure, which developed at a thickness of 200 nm. Due to the change of the growth mode with increasing thickness, the microstructure and surface morphology were also affected by the film thickness. Based on the figure of merit values, we determined that the optimized thickness of the LFTS-grown AGZO film was 200 nm, which was applied in a GaN-LED as a TCL. Successful operation of GaN-LEDs with an optimized AGZO film without Plasma Damage indicates that the LFTS-grown AGZO film is promising Plasma Damage-free TCL for use in GaN-LEDs.
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al2o3 ag al2o3 multilayer thin film passivation prepared by Plasma Damage free linear facing target sputtering for organic light emitting diodes
International Conference on Microelectronics, 2013Co-Authors: Jina Jeong, Han-ki KimAbstract:Abstract Al 2 O 3 /Ag/Al 2 O 3 multilayer passivation prepared by Plasma Damage-free linear facing target sputtering (LFTS) was investigated as a function of inserted Ag thickness. Using antireflection effect of the Ag layer that is sandwiched between dielectric Al 2 O 3 layers, we can obtain a transparent Al 2 O 3 /Ag/Al 2 O 3 multilayer passivation for organic light emitting diodes (OLEDs). It was found that insertion of the Ag layer with optimized thickness between Al 2 O 3 layers lead to improvement of the optical transparency and water vapor transmission rate of the Al 2 O 3 /Ag/Al 2 O 3 multilayer. In addition, current density–voltage–luminescence of an OLED passivated with Al 2 O 3 /Ag (10 nm)/Al 2 O 3 multilayer was similar to that of an OLED with nonpassivated sample, indicating that the performance of an OLED is not affected by high-density Plasma during the LFTS process. Moreover, the lifetime to half initial luminance of an OLED passivated with Al 2 O 3 /Ag (10 nm)/Al 2 O 3 multilayer was longer than that of a nonpassivated sample.
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effect of target substrate distance on the properties of hetero facing target sputtered al ga zn o films
Japanese Journal of Applied Physics, 2013Co-Authors: Hyun-su Shin, Ki-won Seo, Ju-hyun Lee, Han-ki KimAbstract:We investigated the effects of facing target–substrate distance (TSD) on the electrical, optical, structural and morphological properties of Al–Ga–Zn–O (AGZO) films grown by linear facing target sputtering (LFTS) at room temperature to optimize the TSD. Although the optimal TSD for depositing an AGZO film was 3 cm, based on figure of merit values, a longer TSD prevents Plasma Damage of the AGZO films. The AGZO film sputtered under optimized conditions had a sheet resistance of 132 Ohm/square and an optical transmittance of 87.2%. Based on the electrical, optical, structural, and surface properties of AGZO films grown at different TSDs, we suggest a possible mechanism to explain the effects TSD on properties of hetero-sputtered AGZO films prepared by LFTS process.
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characteristics of ito electrode grown by linear facing target sputtering with ladder type magnetic arrangement for organic light emitting diodes
International Conference on Microelectronics, 2009Co-Authors: Jina Jeong, Han-ki Kim, Jaeyoung Lee, Junghwan Lee, Hyodae Bae, Yoonheung TakAbstract:Abstract The preparation and characteristics of indium tin oxide (ITO) electrodes grown using a specially designed linear facing target sputtering (LFTS) system with a ladder type magnet arrangement for organic light emitting diodes (OLED) are described. It was found that the electrical and optical properties of the ITO electrode were critically dependent on the Ar/O 2 flow ratio, while its structural and surface properties remained fairly constant regardless of the Ar/O 2 flow ratio, due to the low substrate temperature during the Plasma Damage-free sputtering. Under the optimized conditions, we obtained an ITO electrode with the lowest sheet resistance of 39.4 Ω/sq and high transmittance of 90.1% (550 nm wavelength) at room temperature. This suggests that LFTS is a promising low temperature and Plasma Damage free sputtering technology for preparing high-quality ITO electrodes for OLEDs and flexible OLEDs at room temperature.
Tetsuya Tatsumi - One of the best experts on this subject based on the ideXlab platform.
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Plasma Damage mechanisms for low k porous sioch films due to radiation radicals and ions in the Plasma etching process
Journal of Applied Physics, 2008Co-Authors: Saburo Uchida, Seigo Takashima, Masaru Hori, Masanaga Fukasawa, Keiji Ohshima, Kazunori Nagahata, Tetsuya TatsumiAbstract:Low dielectric constant (low-k) films have been widely used as insulating materials in ultra-large-scale integrated circuits. Low-k films receive heavy Damage during the Plasma processes of etching or ashing, resulting in an increase in their dielectric constant. In order to realize Damage-free Plasma processes for low-k films, it is essential to determine the influence of radiation, radicals, and ions emitted in the Plasma process on the characteristics of low-k films. We have developed a technique to evaluate the influence of radiation, radicals, ions, and their synergies on films in real Plasma processes and have named it pallet for Plasma evaluation (PAPE). Using the PAPE, Plasma-induced Damage on porous SiOCH films were investigated in dual-frequency capacitively coupled H2∕N2 Plasmas. The Damage was characterized by ellipsometry, Fourier-transform infrared spectroscopy, and thermal desorption spectroscopy. On the basis of the results, the Damage mechanisms associated with vacuum ultraviolet (VUV) an...
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Plasma Damage mechanisms for low k porous sioch films due to radiation radicals and ions in the Plasma etching process
Journal of Applied Physics, 2008Co-Authors: Saburo Uchida, Seigo Takashima, Masaru Hori, Masanaga Fukasawa, Keiji Ohshima, Kazunori Nagahata, Tetsuya TatsumiAbstract:Low dielectric constant (low-k) films have been widely used as insulating materials in ultra-large-scale integrated circuits. Low-k films receive heavy Damage during the Plasma processes of etching or ashing, resulting in an increase in their dielectric constant. In order to realize Damage-free Plasma processes for low-k films, it is essential to determine the influence of radiation, radicals, and ions emitted in the Plasma process on the characteristics of low-k films. We have developed a technique to evaluate the influence of radiation, radicals, ions, and their synergies on films in real Plasma processes and have named it pallet for Plasma evaluation (PAPE). Using the PAPE, Plasma-induced Damage on porous SiOCH films were investigated in dual-frequency capacitively coupled H2∕N2 Plasmas. The Damage was characterized by ellipsometry, Fourier-transform infrared spectroscopy, and thermal desorption spectroscopy. On the basis of the results, the Damage mechanisms associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions were clarified. The Damage was caused not only by ions and radicals but also by VUV and UV radiation emitted by the Plasmas. Moreover, it was found that the synergy between the radiation and the radicals enhanced the Damage.
Jang Hyuk Kwon - One of the best experts on this subject based on the ideXlab platform.
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transparent indium zinc oxide top cathode prepared by Plasma Damage free sputtering for top emitting organic light emitting diodes
Applied Physics Letters, 2006Co-Authors: Han-ki Kim, Kyusung Lee, Jang Hyuk KwonAbstract:We report on Plasma Damage-free sputtering of an indium zinc oxide (IZO) top cathode layer for top-emitting organic light-emitting diodes (TOLEDs) by using a box cathode sputtering (BCS) technique. A sheet resistance of 42.6Ω∕cm and average transmittance above 88% in visible range were obtained even in IZO layers deposited by BCS at room temperature. The TOLED with the IZO top cathode layer shows electrical characteristics and lifetime comparable to a TOLED with only thermally evaporated Mg–Ag cathode. In particular, it is shown that the TOLED with the IZO top cathode film shows very low leakage current density of 1×10−5mAcm2 at reverse bias of −6V. This suggests that there is no Plasma Damage caused by the bombardment of energetic particles during IZO sputtering using the BCS system.
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Plasma Damage free deposition of al cathode on organic light emitting devices by using mirror shape target sputtering
Applied Physics Letters, 2004Co-Authors: Han-ki Kim, Doohee Kim, Kwangwoo Lee, Myungsoo Huh, Soonwook Jeong, Kyuoh Kim, Hyeonggeun Kim, D W Han, Jang Hyuk KwonAbstract:We report on the fabrication of Plasma Damage-free organic light-emitting devices (OLEDs) by using a mirror shape target sputtering (MSTS) technique. It is shown that OLEDs with Al cathode deposited by the MSTS show much lower leakage current (1×10−5mA∕cm2) at reverse bias of −6V, compared to that (1×10−1–∼10−2mA∕cm2 at −6V) of OLEDs with Al cathodes grown by conventional dc magnetron sputtering. This indicates that there is no Plasma Damage, which is caused by the bombardment of energetic particles. This suggests that MSTS could be a useful Plasma Damage-free and low-temperature deposition technique for both top- and bottom-emitting OLEDs and flexible displays.
Saburo Uchida - One of the best experts on this subject based on the ideXlab platform.
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Plasma Damage mechanisms for low k porous sioch films due to radiation radicals and ions in the Plasma etching process
Journal of Applied Physics, 2008Co-Authors: Saburo Uchida, Seigo Takashima, Masaru Hori, Masanaga Fukasawa, Keiji Ohshima, Kazunori Nagahata, Tetsuya TatsumiAbstract:Low dielectric constant (low-k) films have been widely used as insulating materials in ultra-large-scale integrated circuits. Low-k films receive heavy Damage during the Plasma processes of etching or ashing, resulting in an increase in their dielectric constant. In order to realize Damage-free Plasma processes for low-k films, it is essential to determine the influence of radiation, radicals, and ions emitted in the Plasma process on the characteristics of low-k films. We have developed a technique to evaluate the influence of radiation, radicals, ions, and their synergies on films in real Plasma processes and have named it pallet for Plasma evaluation (PAPE). Using the PAPE, Plasma-induced Damage on porous SiOCH films were investigated in dual-frequency capacitively coupled H2∕N2 Plasmas. The Damage was characterized by ellipsometry, Fourier-transform infrared spectroscopy, and thermal desorption spectroscopy. On the basis of the results, the Damage mechanisms associated with vacuum ultraviolet (VUV) an...
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Plasma Damage mechanisms for low k porous sioch films due to radiation radicals and ions in the Plasma etching process
Journal of Applied Physics, 2008Co-Authors: Saburo Uchida, Seigo Takashima, Masaru Hori, Masanaga Fukasawa, Keiji Ohshima, Kazunori Nagahata, Tetsuya TatsumiAbstract:Low dielectric constant (low-k) films have been widely used as insulating materials in ultra-large-scale integrated circuits. Low-k films receive heavy Damage during the Plasma processes of etching or ashing, resulting in an increase in their dielectric constant. In order to realize Damage-free Plasma processes for low-k films, it is essential to determine the influence of radiation, radicals, and ions emitted in the Plasma process on the characteristics of low-k films. We have developed a technique to evaluate the influence of radiation, radicals, ions, and their synergies on films in real Plasma processes and have named it pallet for Plasma evaluation (PAPE). Using the PAPE, Plasma-induced Damage on porous SiOCH films were investigated in dual-frequency capacitively coupled H2∕N2 Plasmas. The Damage was characterized by ellipsometry, Fourier-transform infrared spectroscopy, and thermal desorption spectroscopy. On the basis of the results, the Damage mechanisms associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions were clarified. The Damage was caused not only by ions and radicals but also by VUV and UV radiation emitted by the Plasmas. Moreover, it was found that the synergy between the radiation and the radicals enhanced the Damage.
Hyungcheol Shin - One of the best experts on this subject based on the ideXlab platform.
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thin gate oxide Damage due to Plasma processing
Semiconductor Science and Technology, 1996Co-Authors: Hyungcheol ShinAbstract:Plasma processes cause current to flow through the thin oxide and the resultant Plasma-induced Damage can be simulated and modelled as Damage produced by constant-current (or voltage) electrical stress. Plasma processing causes MOSFET parameter degradation, from which one can deduce the Plasma charging current. Since the scattering of post-Damage device parameters is due to a reproducible variation of stress current across the wafer, one can easily analyse the effect of device geometry on Damage by comparing test structures in the same die rather than the averages over a wafer. We have developed a quantitative model for thin oxide Plasma charging Damage by examining the oxide thickness dependence of the charging current. The model successfully predicts the oxide thickness dependence of Plasma charging. It is shown that Plasma acting on a very thin oxide during processing may be modelled essentially as a current source. Thus the Damage will not be greatly exacerbated as the oxide thickness is further reduced in the future. Although annealing in forming gas can passivate the traps generated during Plasma etching, subsequent Fowler-Nordheim stressing causes more traps to be generated in these devices than in devices that have not been through Plasma etching. The protection diode should be forward biased during processing to safely protect the gate oxide. In CMOS circuits, the drains of the driver circuit can generally act as adequate protection diodes for the oxide regardless of N or P substrate and the polarity of the Plasma charging current. The Plasma stress current can be reduced by reducing the ion density, which is unfortunately linked to the etch rate or directionality, or by reducing the electron temperature. Maintaining a very uniform Plasma over the surface of the wafer, reducing the Plasma charging current during the over-etch time and judicious use of protection diode and antenna design rules will reduce Plasma Damage to an acceptable level for ULSI production even for very thin gate oxides.