• Title/Summary/Keyword: PL characteristics

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Development of Synthetic Zeolites from Scoria for Pesticides Removal in the Golf Course (송이로부터 골프장 농약 제거를 위한 합성 제올라이트의 개발)

  • 감상규;안병준;주창식;이민규
    • Journal of Environmental Science International
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    • v.10 no.6
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    • pp.451-459
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    • 2001
  • Adsorption characteristics of triadimefon and diniconazole(pesticide) by natural zeolite($CLI_N$) and several synthetic zeolites were Investigated. The synthetic zeolites used En this study were as follows: Faujasite synthesized from coal fly ash($FAU_F$); Zeolite synthesized from the mixture of FAU and Na-Pl synthesized from the ratio of Cheju scoria 6 to coal fly ash 4 by weight($(FAU + Na-Pl)_{SF}$); waste fluid catalytic cracking catalyst($FCC_W$). The distribution coefficient, $K_D$ and Freundlich constant, $K_F$ decreased in the fellowing sequence : $FCC_W > FAU_F > (FAU + Na-Pl)_{SF} >CLI_N$ among the zeolites. The distribution coefficient and the adsorption capacity of $(FAU + Na-Pl)_{SF}$ for pesticides were 4.4 and 2.6 times higher for triamefon, and 2.0 and 2.4 times higher for diniconazole than those of $CLI_N$, respectively.

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A Study on the Insulation Characteristics of Organic Thin Films of Au/Pl/Au structure (Au/Pl/Au구조의 유기박막 절연성에 관한 연구)

  • Chon, D.K.;Kim, Y.K.;Cho, C.H.;Lee, K.S.;Choi, Y.I.
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1468-1470
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    • 1998
  • Using a solution of polyamic acid salt obtained in combination with polyimide acid, we successfully prepared thermally stable multilayers(41, 35, 31 layers) films disilane-containing polyimide by Langmuir-Blodgett(LB) technique. We studied the electrically phenomena occurring at the metal(Au)/polyimide(Pl) LB film/metal(Au). Also, we then examined the of Pl LB films by means of current-voltage (I-V) and resistance measurement.

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Deposition and Photoluminescence Characteristics of Silicon Carbide Thin Films on Porous Silicon (다공성실리콘 위의 탄화규소 박막의 증착 및 발광특성)

  • 전희준;최두진;장수경;심은덕
    • Journal of the Korean Ceramic Society
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    • v.35 no.5
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    • pp.486-492
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    • 1998
  • Silicon carbide (SiC) thin films were deposited on the porous silicon substrates by chemical vapour de-position(CVD) using MTS as a source material. The deposited films were ${\beta}$-SiC with poor crystallity con-firmed by XRD measurement. It was considered that the films showed the mixed characteistics of cry-stalline and amorphous SiC where amorphous SiC where amorphous SiC played a role of buffer layer in interface between as-dep films and Si substrate. The buffer layer reduced lattice mismatch to some extent the generally occurs when SiC films are deposited on Si. The low temperature (10K) PL (phtoluminescence) studies showed two broad bands with peaks at 600 and 720 for the films deposited at 1100$^{\circ}C$ The maximum PL peak of the crystalline SiC was observed at 600 nm and the amrophous SiC of 720 nm was also confirmed. PL peak due the amorphous SiC was smaller than that of the crystalline SiC, PL of porous Si might be disapperared due to densification during heat treatment.

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Identification of Phellinus linteus by Morphological Characteristics and Molecular Analysis (형태적.분자생물학적 방법에 의한 Phellinus linteus의 동정에 관한 연구)

  • Kim, Sang-Hee;Kim, Soo-Ho;Sung, Jae-Mo;Harrington, Thomas C.
    • The Korean Journal of Mycology
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    • v.27 no.5 s.92
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    • pp.337-340
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    • 1999
  • The context and upper surface of Phellinus basidiocarp become blackened, rimose and woody. The basidiocarp is sessile, dimidiate and elongate. The basidiospores are pigmented and ovoid to globose. Hymenial setae are $17{\sim}35{\times}6{\sim}8{\mu}m$. Nineteen isolates of Phellinus species, including Phellinus linteus, were used for sequencing of the internal transcribed spacer (ITS) region of the nuclear rDNA. Based on these sequence data, specific primers were designed for identification of Phellinus linteus isolates in Korea. The specific primers were within the ITS1 and ITS2 regions and were nested within the universal primers flanking the spacer regions. A total of four primers (the universal primers ITS-1F and ITS-4, and the specific primers PL-F and PL-R) were used for detection of Phellinus linteus collected in Korea. The length of the four amplification products of Phellinus linteus DNA were 800 bp (ITS-1F/ITS-4), two bands of about 720 bp (ITS-1F/PL-R and PL-F/ITS-4), and 610 bp (PL-F/PL-R). Among 23 isolates of Phellinus species collected in Korea, Thirteen isolates were identified as Phellinus linteus based on the presence of the four bands. The other species produced only the single ITS-1F/ITS-4 product.

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Electrical Leakage Levels Estimated from Luminescence and Photovoltaic Properties under Photoexcitation for GaN-based Light-emitting Diodes

  • Kim, Jongseok;Kim, HyungTae;Kim, Seungtaek;Choi, Won-Jin;Jung, Hyundon
    • Current Optics and Photonics
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    • v.3 no.6
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    • pp.516-521
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    • 2019
  • The electrical leakage levels of GaN-based light-emitting diodes (LEDs) containing leakage paths are estimated using photoluminescence (PL) and photovoltaic properties under photoexcitation conditions. The PL intensity and open-circuit voltage (VOC) decrease because of carrier leakages depending on photoexcitation conditions when compared with reference values for typical LED chips without leakage paths. Changes of photovoltage-photocurrent characteristics and PL intensity due to carrier leakage are employed to assess the leakage current levels of LEDs with leakage paths. The current corresponding to the reduced VOC of an LED with leakage from the photovoltaic curve of a reference LED without leakage is matched with the leakage current calculated using the PL intensity reduction ratio and short-circuit current of the LED with leakage. The current needed to increase the voltage for an LED with a leakage under photoexcitation from VOC of the LED up to VOC of a reference LED without a leakage is identical to the additional current needed for optical turn-on of the LED with a leakage. The leakage current level estimated using the PL and photovoltaic properties under photoexcitation is consistent with the leakage level measured from the voltage-current characteristic obtained under current injection conditions.

Channel Protection Layer Effect on the Performance of Oxide TFTs

  • KoPark, Sang-Hee;Cho, Doo-Hee;Hwang, Chi-Sun;Yang, Shin-Hyuk;Ryu, Min-Ki;Byun, Chun-Won;Yoon, Sung-Min;Cheong, Woo-Seok;Cho, Kyoung-Ik;Jeon, Jae-Hong
    • ETRI Journal
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    • v.31 no.6
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    • pp.653-659
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    • 2009
  • We have investigated the channel protection layer (PL) effect on the performance of an oxide thin film transistor (TFT) with a staggered top gate ZnO TFT and Al-doped zinc tin oxide (AZTO) TFT. Deposition of an ultra-thin PL on oxide semiconductor films enables TFTs to behave well by protecting the channel from a photo-resist (PR) stripper which removes the depleted surface of the active layer and increases the carrier amount in the channel. In addition, adopting a PL prevents channel contamination from the organic PR and results in high mobility and small subthreshold swings. The PL process plays a critical role in the performance of oxide TFTs. When a plasma process is introduced on the surface of an active layer during the PL process, and as the plasma power is increased, the TFT characteristics degrade, resulting in lower mobility and higher threshold voltage. Therefore, it is very important to form an interface using a minimized plasma process.

Analysis of Electrical Characteristics of Oxide Semiconductor of ZnO, SnO2 and ZTO (ZnO, SnO2, ZTO 산화물반도체의 전기적인 특성 분석)

  • Oh, Teresa
    • Korean Journal of Materials Research
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    • v.25 no.7
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    • pp.347-351
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    • 2015
  • To study the characteristics of ZTO, which is made using a target mixed $ZnO:SnO_2=1:1$, the ZnO and $SnO_2$ were analyzed using PL, XRD patterns, and electrical properties. Resulting characteristics were compared with the electrical characteristics of ZnO, $SnO_2$, and ZTO. The electrical characteristics of ZTO were found to improve with increasing of the annealing temperature due to the high degree of crystal structures at high temperature. The crystal structure of $SnO_2$ was also found to increase with increasing temperatures. So, the structure of ZTO was found to be affected by the annealing temperature and the molecules of $SnO_2$; the optical property of ZTO was similar to that of ZnO. Among the ZTO films, ZTO annealed at the highest temperature showed the highest capacitance and Schottky contact.

Anomalous Effect of Hydrogenation on the Optical Characterization $In_{0.5}Ga_{0.5}As$ Quantum Dot Infrared Photodetectors (MBE로 성장된 $In_{0.5}Ga_{0.5}As/GaAs$ 양자점 원적외선 수광소자의 수소화 처리가 광학적 특성에 미치는 특이영향)

  • Lim J.Y.;Song J.D.;Choi W.J.;Cho W.J.;Lee J.I.;Yang H.S.
    • Journal of the Korean Vacuum Society
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    • v.15 no.2
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    • pp.223-230
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    • 2006
  • We have investigated the characteristics of hydrogen (H) plasma treated quantum dot infrared photodetectors (QDIPs). The structure used in this study consists of 3 stacked, self assembled $In_{0.5}Ga_{0.5}As/GaAs$ QD layer separated by GaAs barrier layers that were grown by molecular beam epitaxy. Optical characteristics of QDIPs, such as photoluminescence (PL) spectra and photocurrent spectra, have been studied and compared with each other for the as grown and H plasma treated QDIPs. H plasma treatment, resulted in the splitting of PL peak, which can be attributed to the redistribution of the size of QDs. The activation energies estimated from the temperature dependence of integrated PL intensity for as grown and H plasma treated QDIPs are found to be in good agreement with those determined from corresponding peaks of photocurrent spectra. It is also noted that photocurrent is detected up to 130 K for the H plasma treated QDIP, suggesting the future possibility for the development of infrared photodetectors with high temperature operation.

Influences of Spinodal Decomposition of InGaAsP Layer on Photoluminescence Characteristics (InGaAsP 에피막의 Spinodal분해 조직구조가 Photoluminescence 특성에 미치는 영향)

  • Lee, Jong-Won
    • Korean Journal of Materials Research
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    • v.5 no.8
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    • pp.936-944
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    • 1995
  • The effects of Spinodal decomposition induced phase separated microstructure of InGaAsP/InP heterostructure on photoluminescence(PL) intensity and FWHM(full-width at half maximum) were investigated in this study. Lattice mismatches were measured by double crystal x-ray diffractometer, and the microstructures of phase separated InGaAsP were observed by transmission electron microscopy. It was found that the misfit stress calculated from lattice mismatch was related to the periodicity of Spinodal modulation. Strong dependence of PL intensity and FWHM on the modulation periodicity was also found. For systematic understanding of these observations, the interaction elastic strain energy function induced by misfit stress was proposed. The calculation illustrated that the microstructure of the epilayer such as Spinodal decomposition played an important role in determining the optoelectronic properties such as PL intensity and PL FWHM.

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Petrological characteristics on stone resources of granites in the Pocheon-Euijeongbu area (포천-의정부지역 화강암류 석재자원의 암석학적 특성연구)

  • 윤현수
    • The Journal of the Petrological Society of Korea
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    • v.6 no.1
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    • pp.34-44
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    • 1997
  • The Jurassic granites, commercially called Yangu stone in the Pocheon-Euijeongbu area, have generally compact and coarse-grained textures, which could be classified into two types; grey granite(Gg) and light pink granite(Gp). Specific gravity, absorption ratio and prosity of Gg and Gp in physical property are 2.64 and 2.61, 0.32 % and 0.44 %, 0.86% and 1.13 %, respectively. These higher values of two latters of Gp than those of Gg are due to the more abundant microcracks in Gp. Compressive strength og Gg than those of Gg are due to more abundant microcracks in Gp. Compressive strength og Gg and Gp are 1,726 kg/cm2 and 1,717 kg/cm, respectively and bestrength has a positive proportion with Qz+Af+Pl(quartz+alkali feldspar+plagioclase) modes without trending with Bt+Ac(biotite+accessories). Tensile strength has the positive proportions with Qz+Af+Pl and Bt+Ac. While Bt+Ac has a negative trend with abrasive hardness, Qz+A+Pl shows a positive one. These may suggest Qz+Af+Pl mainly affects on strenghts potentional dimension stone than Gp.

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