• Title/Summary/Keyword: top emission

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Nanophotonics of Hexagonal Lattice GaN Crystals Fabricated using an Electron Beam Nanolithography Process

  • Lee, In-Goo;Kim, Keun-Joo;Jeon, Sang-Cheol;Kim, Jin-Soo;Lee, Hee-Mok
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.4
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    • pp.14-17
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    • 2006
  • A thin GaN semiconducting film that grows on sapphires due to metalorganic chemical vapor deposition was machined for nanophotonic applications. The thin film had multilayered superlattice structures, including nanoscaled InGaN layers. Eight alternating InGaN/GaN multilayers provided a blue light emission source. Nanoscaled holes, 150 nm in diameter, were patterned on polymethylmethacrylate (PMMA) film using an electron beam lithography system. The PMMA film blocked the etching species. Air holes, 75 nm in diameter, which acted as blue light diffraction sources, were etched on the top GaN layer by an inductively coupled plasma etcher. Hexagonal lattice photonic crystals were fabricated with 230-, 460-, 690-, and 920-nm pitches. The 450-nm wavelength blue light provided the nanodiffraction destructive and constructive interferences phenomena, which were dependent on the pitch of the holes.

Meat analog as future food: a review

  • Ismail, Ishamri;Hwang, Young-Hwa;Joo, Seon-Tea
    • Journal of Animal Science and Technology
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    • v.62 no.2
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    • pp.111-120
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    • 2020
  • The definition of meat analog refers to the replacement of the main ingredient with other than meat. It also called a meat substitute, meat alternatives, fake or mock meat, and imitation meat. The increased importance of meat analog in the current trend is due to the health awareness among consumers in their diet and for a better future environment. The factors that lead to this shift is due to low fat and calorie foods intake, flexitarians, animal disease, natural resources depletion, and to reduce greenhouse gas emission. Currently, available marketed meat analog products are plant-based meat in which the quality (i.e., texture and taste) are similar to the conventional meat. The ingredients used are mainly soy proteins with novel ingredients added, such as mycoprotein and soy leghemoglobin. However, plant-based meat is sold primarily in Western countries. Asian countries also will become a potential market in the near future due to growing interest in this product. With the current advance technology, lab-grown meat with no livestock raising or known as cultured meat will be expected to boost the food market in the future. Also, insect-based products will be promising to be the next protein resource for human food. Nevertheless, other than acceptability, cost-effective, reliable production, and consistent quality towards those products, product safety is the top priority. Therefore, the regulatory frameworks need to be developed alongside.

Flexible Low Power Consumption Active-Matrix OLED Displays

  • Hack, Mike;Chwang, Anna;Hewitt, Richard;Brown, Julie;Lu, JengPing;Shih, ChinWen;Ho, JackSon;Street, R.A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.609-613
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    • 2005
  • Advanced mobile communication devices require a bright, high information content display in a small, light-weight, low power consumption package. In this paper we will outline our progress towards developing such a low power consumption active-matrix flexible OLED ($FOLED^{TM}$) display. Our work in this area is focused on three critical enabling technologies. The first is the development of a high efficiency long-lived phosphorescent OLED ($PHOLED{TM}$) device technology, which has now proven itself to be capable of meeting the low power consumption performance requirements for mobile display applications. Secondly, is the development of flexible active matrix backplanes, and for this our team are employing poly-Si TFTs formed on metal foil substrates as this approach represents an attractive alternative to fabricating poly-Si TFTs on plastic for the realization of first generation flexible active matrix OLED displays. Unlike most plastics, metal foil substrates can withstand a large thermal load and do not require a moisture and oxygen permeation barrier. Thirdly, the key to reliable operation is to ensure that the organic materials are fully encapsulated in a package designed for repetitive flexing. We also present progress in operational lifetime of encapsulated T-PHOLED pixels on planarized metal foil and discuss PHOLED encapsulation strategy.

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Nanotextured Si Solar Cells on Microtextured Pyramidal Surfaces by Silver-assisted Chemical Etching Process

  • Parida, Bhaskar;Choi, Jaeho;Palei, Srikanta;Kim, Keunjoo;Kwak, Seung Jong
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.4
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    • pp.212-220
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    • 2015
  • We investigated nanotextured Si solar cells using the silver-assisted chemical etching process. The nanotexturing process is very sensitive to the concentration of chemical etching solution. The high concentration process results in a nanowire formation for the nanosurfaces and causes severe surface damage to the top region of the micropyramids. These nanowires show excellent light absorption in photoreflectance spectra and radiative light emission in photoluminescence spectra. However, the low concentration process forms a nano-roughened surface and provides high minority carrier lifetimes. The nano-roughened surfaces of the samples show the improved electrical cell properties of quantum efficiency, conversion efficiency, and cell fill factor due to the reduction in the formation of the over-doped dead layer.

Evaluation of Key Success Factors for Web Design in Taiwan's Bike Case Study

  • LAI, I-Sung;HUANG, Yung-Fu;SIANG, Jie-Hua;WENG, Ming-Wei
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.11
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    • pp.927-937
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    • 2020
  • Global warming awareness through energy conservation is growing due to the regulatory policies issued by governments and voluntary organization that established carbon emission limits. Transportation is one of the major contributors to carbon emissions. Bike will be simultaneously saving money, getting fit and helping to reduce global warming. Web design has been identified as a key factor for the acceptance and success of the websites and electronic commerce. The purpose of this research is to investigate the effective implementation of the proposed Analytic Hierarchy Process (AHP) technique on a bike case study whose company (Bike Company) is involved in web design for a critical component in the demonstration. Survey research used a variety of data collection methods, with the most common being questionnaires and interviews of some exporters. The research results reveal that the top five key success factors are Good reputation, Transaction security, Ease of use, Promotion, and Diversified choices, which provide the guidelines and directions for decision-makers to design effective websites in the current competitive business scenario. The major findings of this study are suggesting that Internet marketing channels are securing the company's relevance, together with paving the way for methods to increase web traffic.

Multidimensional ZnO light-emitting diode structures grown by metal organic chemical vapor deposition on p-Si (p형 Si 기판위에 성장된 ZnO 다층형복합구조의 이종접합구조 LED 제작)

  • Kim, Dong-Chan;Kong, Bo-Hyun;Han, Won-Suk;Choi, Mi-Kyung;Cho, Hyung-Koun;Lee, Jong-Hun;Kim, Hong-Seung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.84-84
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    • 2008
  • A multidimensional ZnO light-emitting diode LEDstructure comprising film/nanorods/substrate was fabricated on a p-type Si substrate using metal organic chemical vapor deposition at relatively low growth temperature. The filmlike top layer used for the metal contact was continuously formed on the ZnO nanorods by varying the growth conditions and the resulting structure allowed us to utilize the nanorods with intense emission as an active layer. We investigated the performance of the resulting multidimensional LED. An extremely high breakdown voltage and low reverse leakage current as well as typical rectification behavior were observed in the I-V characteristics.

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Inverted OLED Structure for 3.5 inch Full Color AMOLED Display on a-Si TFT Backplane

  • Park, Jae-Hee;Park, Jae-Young;Hwang, Kwang-Jo;Choi, Hee-Dong;Myoung, Nho-Hoon;Lee, Seok-Jong;Park, Seung-Chul;Kim, Jung-Bum;Hahm, Yun-Hye;Noh, Jeoung-Kwen;Lee, Jung-Hyoung;Kim, Jong-Seok;Kang, Min-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.51-54
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    • 2007
  • Top-emission 3.5 inch qVGA IOD (Inverted AMOLED) was fabricated with inverted EL structure driven by a-Si TFT backplane. In order to get stable driving TFT, we used FCP(Field Control Plate) layer which was connected with the source of the driving TFT. And we developed planarization process to planarize the cathode layer which was the bottom layer of inverted OLED. Our unique IOD structure is “a-Si TFT/ Al(Cathode)/ LiF/ LG-201(ETL)/ EML(RGB)/ HTL/ LG-101(HIL & Buffer layer)/ IZO(Anode)”. LG-201(ETL) layer was studied for more efficient electron injection from cathode to EML, and LG-101(HIL & Buffer layer) covered by IZO anode was also explored for decreasing the EL surface damage.

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Preparation and characterization of TiO2 membrane on porous 316 L stainless steel substrate with high mechanical strength

  • Mohamadi, Fatemeh;Parvin, Nader
    • Membrane and Water Treatment
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    • v.6 no.3
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    • pp.251-262
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    • 2015
  • In this work the preparation and characterization of a membrane containing a uniform mesoporous Titanium oxide top layer on a porous stainless steel substrate has been studied. The 316 L stainless steel substrate was prepared by powder metallurgy technique and modified by soaking-rolling and fast drying method. The mesoporous titania membrane was fabricated via the sol-gel method. Morphological studies were performed on both supported and unsupported membranes using scanning electron microscope (SEM) and field emission scanning microscope (FESEM). The membranes were also characterized using X-ray diffraction (XRD) and $N_2$-adsorption / desorption measurement (BET analyses). It was revealed that a defect-free anatase membrane with a thickness of $1.6{\mu}m$ and 4.3 nm average pore size can be produced. In order to evaluate the performance of the supported membrane, single-gas permeation experiments were carried out at room temperature with nitrogen gas. The permeability coefficient of the fabricated membrane was $4{\times}10^{-8}\;lit\;s^{-1}\;Pa^{-1}\;cm^{-1}$.

Photoactive Layer Formation with Oven Annealing for a Carbon Electrode Perovskite Solar Cell

  • Kim, Kwangbae;Song, Ohsung
    • Korean Journal of Materials Research
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    • v.30 no.11
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    • pp.595-600
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    • 2020
  • The photovoltaic properties of perovskite solar cells (PSCs) with a carbon electrode fabricated using different annealing processes are investigated. Perovskite formation (50 ℃, 60 min) using a hot-plate and an oven is carried out on cells with a glass/fluorine doped TiO2/TiO2/ZrO2/carbon structure, and the photovoltaic properties of the PSCs are analyzed using a solar simulator. The microstructures of the PSCs are characterized using an optical microscope, a field emission scanning electron microscope, and an electron probe micro-analyzer (EPMA). Photovoltaic analysis shows that the energy conversion efficiency of the samples fabricated using the hot-plate and the oven processes are 2.08% and 6.90%, respectively. Based on the microstructure of the samples and the results of the EPMA, perovskite is formed locally on the carbon electrode surface as the γ-butyrolactone (GBL) solvent evaporates and moves to the top of the carbon electrode due to heat from the bottom of the sample during the hot plate process. When the oven process is used, perovskite forms evenly inside the carbon electrode, as the GBL solvent evaporates extremely slowly because heat is supplied from all directions. The importance of the even formation of perovskite inside the carbon electrode is emphasized, and the feasibility of oven annealing is confirmed for PSCs with carbon electrodes.

Variations of Interface Potential Barrier Height and Leakage Current of (Ba, Sr)$TiO_3$ Thin Films Deposited by Sputtering Process

  • Hwang, Cheol-Seong;Lee, Byoung-Taek
    • The Korean Journal of Ceramics
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    • v.2 no.2
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    • pp.95-101
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    • 1996
  • Variations of the leakage current behaviors and interface potential barrier $({\Phi}_B)$ of rf-sputter deposited (Ba, Sr)$TiO_3$ (BST) thin films with thicknesses ranging from 20 nm to 150nm are investigated as a function of the thickness and bias voltages. The top and bottom electrodes are dc-sputter-deposited Pt films. ${\Phi}_B$ critically depends on the BST film deposition temperature, postannealing atmosphere and time after the annealing. The postannealing under $N_2$ atmosphere results in a high interface potential barrier height and low leakage current. Maintaining the BST capacitor in air for a long time reduces the ${\Phi}_B$ from about 2.4 eV to 1.6 eV due to the oxidation. ${\Phi}_B$ is not so dependent on the film thickness in this experimental range. The leakage conduction mechanism is very dependent on the BST film thickness; the 20 nm thick film shows tunneling current, 30 and 40 nm thick films show Shottky emission current.

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