• Title/Summary/Keyword: Cell Trapping Device

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Light Trapping in Silicon Based Tandem Solar Cell: A Brief Review

  • Iftiquar, Sk Md;Park, Hyeongsik;Dao, Vinh Ai;Pham, Duy Phong;Yi, Junsin
    • Current Photovoltaic Research
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    • v.4 no.1
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    • pp.1-7
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    • 2016
  • Among the various types of solar cells, silicon based two terminal tandem solar cell is one of the most popular one. It is designed to split the absorption of incident AM1.5 solar radiation among two of its component cells, thereby widening the wavelength range of external quantum efficiency (EQE) spectra of the device, in comparison to that of a single junction solar cell. In order to improve the EQE spectra further and raise short circuit current density ($J_{sc}$) an optimization of the tradeoff between the top and bottom cell is needed. In an optimized cell structure, the $J_{sc}$ and hence efficiency of the device can further be enhanced with the help of light trapping scheme. This can be achieved by texturing front and back surface as well as a back reflector of the device. In this brief review we highlight the development of light trapping in the silicon based tandem solar cell.

Ultrashort Pulsed Laser Machining for Biomolecule Trapping

  • Choi, Hae-Woon;Farson, Dave F.;Lee, L.James;Lee, Ho
    • Journal of the Optical Society of Korea
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    • v.13 no.3
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    • pp.335-340
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    • 2009
  • Ultrashort pulse laser drilling of polycarbonate track-etched membrane (pTEM) material was used to fabricate a mouse embryo cell trapping device. Holes with a diameter of $2{\mu}m$ to $5{\mu}m$ were fabricated on a $10{\mu}m$ thick membrane using a femtosecond laser with a 150 fs pulse width and 775 nm wavelength and multiple-pulse irradiation. In cell trapping tests, the overall cell occupancy of the machined holes in the fabricated pTEM was found to be more than 80%. The results of a single pulse and multiple pulse irradiation were compared in terms of the surface quality. It was generally found that a single pulse with high energy was less desirable than irradiation with multiple pulses of lower energy.

A Dielectrophoresis Microfluidic Device for Trapping Bioparticles at Low Voltage and Frequency

  • Jeong, Jin-Tae;Shin, Hyun-Min;Kim, Duwoon;Lee, Kyeong-Hwan
    • Journal of Biosystems Engineering
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    • v.41 no.1
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    • pp.60-65
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    • 2016
  • Purpose: The necessity for precise manipulation of bioparticles has greatly increased in the fields of bioscience, biomedical, and environmental monitoring. Dielectrophoresis (DEP) is considered to be an ideal technique to manipulate bioparticles. The objective of this study is to develop a DEP microfluidic device that can trap fluorescent beads, which mimic bioparticles, at the low voltage and frequency of the sinusoidal signal supplied to the microfluidic device. Methods: A DEP microfluidic device, which is composed of polydimethylsiloxane (PDMS) channels and interdigitated electrode networks, is fabricated to trap fluorescent beads. The geometry of the interdigitated electrodes is determined through computational simulation. To determine the optimum voltage and frequency of the sinusoidal signal supplied to the device, the experiments of trapping beads are conducted at various combinations of voltage and frequency. The performance of the DEP microfluidic device is evaluated by investigating the correlation between fluorescent intensities and bead concentrations. Results: The optimum ratio of the widths between the negative and positive electrodes was 1:4 ($20:80{\mu}m$) at a gap of $20{\mu}m$ between the two electrodes. The DEP electrode networks were fabricated based on this geometry and used for the bead trapping experiments. The optimum voltage and frequency of the supplied signal for trapping fluorescent beads were 15 V and 5 kHz, respectively. The fluorescent intensity of the trapped beads increased linearly as the bead concentration increased. The coefficient of determination ($R^2$) between the fluorescent intensity and the bead concentration was 0.989. Conclusions: It is concluded that the microfluidic device developed in this study is promising for trapping bioparticles, such as a cell or virus, if they are conjugated to beads, and their concentration is quantified.

Present Status of Thin Film Solar Cells Using Textured Surfaces: A Brief Review

  • Park, Hyeongsik;Iftiquar, S.M.;Le, Anh Huy Tuan;Ahn, Shihyun;Kang, Junyoung;Kim, Yongjun;Yi, Junsin;Kim, Sunbo;Shin, Myunghun
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.5
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    • pp.275-279
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    • 2016
  • This is a brief review on light trapping in Si based thin film solar cells with textured surfaces and transparent conducting oxide front electrodes. The light trapping scheme appears to be essential in improving device efficiency over 10%. As light absorption in a thin film solar cells is not sufficient, light trapping becomes necessary to be effectively implemented with a textured surface. Surface texturing helps in the light trapping, and thereby raises short circuit current density and its efficiency. Such a scheme can be adapted to single junction as well as tandem solar cell, amorphous or micro-crystalline devices. A tandem cell is expected to have superior performance in comparison to a single junction cell and random surface textures appears to be preferable to a periodic structures.

Current status of light trapping in module cover glass for PV module (광 포획 태양전지 모듈 커버용 유리기판 기술 현황)

  • Park, Hyeongsik;Jung, Jaesung;Shin, Myunghun;Kim, Sunbo;Yi, Junsin
    • Current Photovoltaic Research
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    • v.4 no.3
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    • pp.119-123
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    • 2016
  • We discussed various cover glass substrates available for photovoltaic (PV) modules, and investigated the fabrication methods of light trapping structures for the efficiency enhancement of PV modules: wet and dry etching or laser and direct patternings. We also introduced the analysis of haze at etched glass surfaces as a function of wavelength and also presented a anti-reflection coating technology for PV module.

Reliability Analysis by Lateral Charge Migration in Charge Trapping Layer of SONOS NAND Flash Memory Devices (SONOS NAND 플래시 메모리 소자에서의 Lateral Charge Migration에 의한 소자 안정성 연구)

  • Sung, Jae Young;Jeong, Jun Kyo;Lee, Ga Won
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.4
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    • pp.138-142
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    • 2019
  • As the NAND flash memory goes to 3D vertical Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) structure, the lateral charge migration can be critical in the reliability performance. Even more, with miniaturization of flash memory cell device, just a little movement of trapped charge can cause reliability problems. In this paper, we propose a method of predicting the trapped charge profile in the retention mode. Charge diffusivity in the charge trapping layer (Si3N4) was extracted experimentally, and the effect on the trapped charge profile was demonstrated by the simulation and experiment.

Analysis Trap and Device Characteristic of Silicon-Al2O3-Nitride-Oxide-Silicon Memory Cell Transistors using Charge Pumping Method (Charge Pumping Method를 이용한 Silicon-Al2O3-Nitride-Oxide-Silicon Flash Memory Cell Transistor의 트랩과 소자)

  • Park, Sung-Soo;Choi, Won-Ho;Han, In-Shik;Na, Min-Gi;Lee, Ga-Won
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.7
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    • pp.37-43
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    • 2008
  • In this paper, the dependence of electrical characteristics of Silicon-$Al_2O_3$-Nitride-Oxide-Silicon (SANOS) memory cell transistors and program/erase (P/E) speed, reliability of memory device on interface trap between Si substrate and tunneling oxide and bulk trap in nitride layer were investigated using charge pumping method which has advantage of simple and versatile technique. We analyzed different SANOS memory devices that were fabricated by the identical processing in a single lot except the deposition method of the charge trapping layer, nitride. In the case of P/E speed, it was shown that P/E speed is slower in the SANOS cell transistors with larger capture cross section and interface trap density by charge blocking effect, which is confirmed by simulation results. However, the data retention characteristics show much less dependence on interface trap. The data retention was deteriorated as increasing P/E cycling number but not coincides with interface trap increasing tendency. This result once again confirmed that interface trap independence on data retention. And the result on different program method shows that HCI program method more degraded by locally trapping. So, we know as a result of experiment that analysis the SANOS Flash memory characteristic using charge pumping method reflect the device performance related to interface and bulk trap.

엔지니어 터널베리어($SiO_2/Si_3N_4/SiO_2$)와 고유전율($HfO_2$) 트랩층 구조를 가지는 비휘발성 메모리의 멀터레벨에 관한 연구

  • Yu, Hui-Uk;Park, Gun-Ho;Lee, Yeong-Hui;Jeong, Hong-Bae;Jo, Won-Ju
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.56-56
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    • 2009
  • In this study, we fabricated the engineered $SiO_2/Si_3N_4/SiO_2$(ONO) tunnel barrier with high-k $HfO_2$ trapping layer for application high performance flash MLC(Multi Level Cell). As a result, memory device show low operation voltage and stable memory characteristics with large memory window. Therefore, the engineered tunnel barrier with ONO stacks were useful structure would be effective method for high-integrated MLC memory applications.

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Analysis of the Interface Trap Effect on Electrical Characteristic and Reliability of SANOS Memory Cell Transistor (SANOS 메모리 셀 트랜지스터에서 Tunnel Oxide-Si Substrate 계면 트랩에 따른 소자의 전기적 특성 및 신뢰성 분석)

  • Park, Sung-Soo;Choi, Won-Ho;Han, In-Shik;Na, Min-Ki;Om, Jae-Chul;Lee, Seaung-Suk;Bae, Gi-Hyun;Lee, Hi-Deok;Lee, Ga-Won
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.94-95
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    • 2007
  • In this paper, the dependence of electrical characteristics of Silicon-$Al_2O_3$-Nitride-Oxide-Silicon (SANOS) memory cell transistors and program speed, reliability of memory device on interface trap between Si substrate and tunneling oxide was investigated. The devices were fabricated by the identical processing in a single lot except the deposition method of the charge trapping layer, nitride. In the case of P/E speed, it was shown that P/E speed is slower in the SONOS cell transistors with larger interface trap density by charge blocking effect, which is confirmed by simulation results. However, the data retention characteristics show much less dependence on interface trap. Therefore, to improve SANOS memory characteristic, it is very important to optimize the interface trap and charge trapping layer.

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