• 제목/요약/키워드: microcrystalline

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Improvement of Retention and Memory Window Characteristics by Crystallization in Hydrogenated Microcrystalline Silicon-germanium

  • 김지웅;김태용;이준신
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.237.2-237.2
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    • 2014
  • 이번 연구는 system-on-panel에 적용하기 위한 비휘발성 메모리의 전하보유시간 및 메모리 윈도우 특성 향상에 관한 연구이다. 이를 위해 SiO2/SiOX/SiOXNY의 메모리 구조를 이용하였으며, 채널층으로 결정화 온도에 따른 수소화된 미세결정 실리콘-게르마늄을 이용하였다. 채널 층으로 사용된 수소화된 미세결정 실리콘-게르마늄은 비정질 실리콘-게르마늄보다 더 낮은 bandgap과 더 적은 defect density로 인하여 더 향상된 전하보유시간 및 메모리 윈도우를 얻을 수 있었다. 결정화가 거의 이루어지지 않은 실리콘-게르마늄 비휘발성 메모리의 경우 약 4.9V의 메모리 윈도우를 얻을 수 있었다. 반면 300oC에서 약 43.4%의 결정화가 이루어진 실리콘-게르마늄의 메모리 윈도우는 약 5.9V로 약 17%의 향상이 있으며, 10년 후 74.5%의 높은 전하보유시간을 가졌다.

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Metal-assisted grown Si films and semiconducting nanowires for solar cells

  • 김준동
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2010년도 춘계학술발표대회
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    • pp.13-13
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    • 2010
  • The solar energy conversion will take 10 % global energy need by 2033. A thin film type solar cell has been considered as one of the promising candidates for a large area applicable solar cell fabrication at a low cost. The metal-assisted growth of microcrystalline Si (mc-Si) films has been reported for a quality Si film synthesis at a low temperature. It discusses the spontaneous growth of a Si film above a metal-layer for a thin film solar cell. Quite recently, a substantial demand of nanomaterials has been addressed for cost-effective solar cells. The nanostructure provides a large photoactive surface at a fixed volume, which is an advantage in the effective use of solar power. But the promising of nanostructure active solar cell has not been much fulfilled due mainly to the difficulty in architecture of nanostructures. We present here the Si nanowire (SiNW)-embedded Schottky solar cell. Multiple SiNWs were connected to two different metals to form a Schottky or an ohmic contact according to the metal work function values. It discusses the scheme of rectifying contact between metals and SiNWs and the SiNW-embedded Schottky solar cell performances.

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Isolation and Characterization of Bacillus sp. KD1014 Producing Carboxymethyl-Cellulase (Isolation and characterization of Bacillus sp. KD1014 producing carboxymethyl-cellulase)

  • Lee, Kyung Dong;Kim, Jong Ho;Kim Hoon
    • Journal of Microbiology
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    • 제34권4호
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    • pp.305-310
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    • 1996
  • A microorganism producing carboxymethyl-cellulase (CMCase) was isolated from 300 soil and compost samples. The isolate was identified as Bacillus sp. by $Biolog^{TM}$ test and fatty acid analysis, and named as Bacillus sp. KD1014. The isolate could degrade, in addition to CMC, various kinds of polysaccharides such as levan, xylan, starch, and filter paper but hardly degrade microcrystalline Avicel. The optimum growth and CMCase production of the isolate was observed between 16-and 25 hr-culture at 45$^{\circ}C$ and pH 5.0. The maximum CMCase activity was observed at pH 4.5 and 6$0^{\circ}C$. The CMCase was found to bind to Avicel. The CMCase was internally cleaved as growth continued. When crude supernatant was used for activity staining, three major bands were detected on a native gel, however, only one major band was detected on a denaturating gel after removal of the detergent.

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양극산화 알루미늄피막을 이용한 박막트랜지스터의 구성에 관한 연구 (A Study on the TFT Fabrication Using Anodized Aluminium Oxide Film)

  • 김봉흡;홍창희
    • 대한전기학회논문지
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    • 제31권9호
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    • pp.74-81
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    • 1982
  • One of the stable thin film transistor fabricated by cadmium suifide with the anodized aluminium oxide as gate material. The principle of the operation for the device is based on the control mechanism of injected majority carricrs to the wide band gap semiconductor, that is cadmium sulfide, by means of the function of the gate control. The fabricated device constructed by evaporating CdS layer in the form of microcrystalline on the oxided thin film characterized by ea, 80 as voltage amplification factor, 1/100 mho as transconductance, 8 kohm as dynamic output resistance, furthermore gain band width products is about 15 MHz.

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RF 바이어스가 수소화된 나노결정실리콘 박막에 미치는 영향 (Influence of radio frequency bias on hydrogenated nanocrystalline silicon thin film)

  • 김인교;이형철;염근영
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2009년도 춘계학술대회 논문집
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    • pp.98-98
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    • 2009
  • Hydrogenated nano-, microcrystalline silicon 박막(nc-, ${\mu}c-Si:H$)은 박막 트랜지스터 및 실리콘 박막형 태양전지등에 널리 쓰이고 있다. 이러한 결정화 실리콘 박막을 내장형 안테나를 사용하여 고밀도 플라즈마를 발생시킬 수 있는 장치를 통하여 증착 후 열처리 공정이 없는 방법을 사용하여 박막을 제작하였다. 특히, 증착시 기판에 바이어스를 함께 인가하므로 증착된 박막의 결정화에 미치는 영향에 관한 연구를 하였다. 기판에 인가된 바이어스가 60W일 때 가장 높은 결정화율을 보이는 것을 알 수 있었다.

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Disintegrating Behavior of A Rapidly Disintegrating Famotidine Tablet Formulation

  • Park, Jeong-Sook;Shin, Kwang-Hyun;Park, Jong-Bum;Lee, Si-Beum;Hwang, Sung-Joo
    • Journal of Pharmaceutical Investigation
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    • 제37권5호
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    • pp.275-280
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    • 2007
  • A rapidly disintegration famotidine tablet formulation in the oral cavity was developed using microcrystalline cellulose (MCC) and low-substituted hydroxypropyl cellulose (L-HPC), or additionally cropovidone as an internal disintegrant. Effects of disintegrants on the disintegration time in vitro and hardness were evaluated. Average wetting time of the tablets prepared in scale-up manufacturing process was less than 15 sec. Among the formulations tested, the tablet prepared with crospovidone as an internal disintegrant and Emcocel $90M^{(R)}$ as an external disintegrant showed fastest disintegration. These results may suggest that crospovidone and Emcocel $90M^{(R)}$ possessed excellent wetting nature, which result in the rapid disintegration of tablet.

동시당화 발효법에 의한 볏짚의 Acetone-Butanol 발효 (Acetone-Butanol Fermentation of Rice Straw by Simultaneous Saccharification and Fermentation)

  • 권기석;전영숙;김병홍
    • 미생물학회지
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    • 제26권3호
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    • pp.278-282
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    • 1988
  • 볏짚을 이용하여 acetone-butanol을 생산하기 위해 전처리한 볏짚을 C. acetobutylicum KCTC 1037(ATCC 4259)과 Trichoderma viride로부터 얻은 섬유소 분해효소를 이용하여 동시당화 발효법 (SSF)으로 발효하였다. Ball-mill로 처리한 볏짚을 SSF로 발효한 결과 acetate와 butyrate안을 생산하였으나, alkali로 전처리한 기질은 230 mM 이상의 solvent를 생산하였다. 이와 같은 발효의 차이는 볏짚에는 alkali 처리로 분해되는 물질이 있으며, 이 물질이 solvent 생산을 저해하기 때문인 것으로 판단된다. 이러한 solvent 생산 저해물질은 물이나 유기용매에 불용성으로 lignin 유도체 혹은 잔류농약으로 추측된다.

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의약품 제조설계 및 조작분석의 최적화에 관한 연구 - 정제제조의 최적화 (Mathematical Optimization Techniques in Drug Product Design and Process Analysis. Optimization Techniques in Tablet Design)

  • 김용배
    • 약학회지
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    • 제18권1호
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    • pp.49-58
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    • 1974
  • Tablet product design problem was structured as constrained optimization problem and subsequently solved by multiple regression analysis and Lagrangian method of optimization. Aluminum flufenamate was the drug chosen and microcrystalline cellulose nad starch were the binder and disintegrant, respectivley. The effect of the binder and disintegrant concentration on tablet hardness, friability, volume, in vitro release rate, and urinary excretion rate of drug in human subjects was recorded. Since a reasonably rapid release rate of drug is generally an important objective in the design of solid dosage form, optimization of this parameter was employed in studying the applicability of constrained optimization to a pharmaceutical product design problem. In addition to finding optimal sitivity analysis studies to such problems was also illustratd. It would appear that prediction of the in vivo t$_{50%}$ response from a knowledge of the incitro t$_{50%}$ response can be made fairly accurately for the tablet system used in this study.

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Multi-Electron Donor Organic Molecules Containing Hydroquinone Methyl-Ether as Redox Active Units

  • Khandelwal, Manish;Hwang, In-Chul;Nair, Prakash Chandran R.;Lee, Jung-Woo
    • Bulletin of the Korean Chemical Society
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    • 제33권4호
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    • pp.1190-1198
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    • 2012
  • Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.

카올리나이트의 상전이반응 과정 연구 (An Investigation of the Transformation Sequence from Kaolinite to Mullite)

  • 이수정;김윤중;문희수
    • 한국광물학회지
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    • 제11권1호
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    • pp.32-44
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    • 1998
  • The transformation sequence of kaolinite to mullite is examined with new electron diffraction data obtained mainly by an energy filtering transmission electron microscope. Kaolinite is transformed finally into mullite and cristobalite through several steps of continuous reactions by heating, which result in metakaolinite, microcrystalline spinel-type phase and amorphous silica. Metakaolinite maintains a short-range order in its structure ven at $920^{\circ}C$. Spinel phase results from a topotactictransformation of metakaolinite apart from the breakdown of metakaolinite structure. the first strong exothermic peak on DTA curve is mainly due to the extraction of amorphous silica from metakaolinite and the gradual nucleation of mullite. Metakaolinite decomposes around$ 940^{\circ}C$ to mullite that doesn't show a clear crystallographic relationship to the parent metakaolinite structure. However, spinel phase produced previously is maintained. The initially formed spinel and mullite phases are suggested to be Al-rich, but progressively gain Si in their structures at higher temperatures. Spinel phase decomposes completely through a second weak exothermic reaction promoting the growth of mullite, and crystallization of amorphous silica to cristobalite.

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