• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.939-942
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• 2007

We investigated the characteristics of UTB-SOI pMOSFETs with SOI thickness($T_{SOI}$) ranging from 10 nm to 1 nm and evaluated the dependence of electrical characteristics on the silicon surface orientation. As a result, it is found that the subthreshold characteristics of (100)-surface UTB-SOI pMOSFETs were superior to (110)-surface. However, the hole mobility of (110)-surface were larger than that of (100)-surface. Especially, the enhancement of effective hole mobility at the effective field of 0.1 MV/cm was observed from 3-nm to 5-nm SOI thickness range.

• Journal of the Korean Society of Radiology
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• v.4 no.4
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• pp.37-40
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• 2010

In this paper, transport properties of charge carrier which is produced by x-ray exposure were investigated.. It is the research of charge transport and specific property of trap that is performed in direct digital x-ray image receptor. We measured transit time and drift mobility of charge carriers of a-Se photoconductor using time-of-flight method. We made a testing glass with a-Se of $100{\mu}m$ thickness on corning glass using thermal evaporation method. As a result of this experiment, electron and hole transit time was each $229.17{\mu}s$ and $8.73{\mu}s$ at $10V/{\mu}m$ electric field and drift mobility was each $0.00174cm^2/V{\cdot}s$, $0.04584cm^2/V{\cdot}s$. But the results shows us different measurement value of electron and charge drift mobility and it was investigated about charge transport properties and trap mechanism.

• Electrical & Electronic Materials
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• v.9 no.6
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• pp.564-571
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• 1996

We calculated the drift-velocities of electrons and holes of I $n_{0.53}$(A $l_{x}$G $a_{1-x}$ )$_{0.47}$As, which is used for semiconductor materials of high performance HBTs, along with the various doping concentrations and Al mole fractions as well as the electric fields by Monte Carlo experiment. Especially, for the valence bands the accuracy of hole-drift-velocity was improved in the consideration of intervalley scattering due to the inelastic scattering of acoustic phonon. From the results the empirical formulas of the low- and high field mobility of electrons and holes were extracted by using nonlinear least square fitting method. The accuracy of the formulas was proved by comparing the formula of low-field electron mobility as well as drift-velocity of I $n_{0.53}$ G $a_{0.47}$As and of low-field hole mobility of GaAs with the measured values, where the error was below 10%. For the high-field mobilities of electron and hole the results calculated by the formulas were very well matched with the MC experimental results except at the narrow field range where the electrons produced the velocity overshoot and the corresponding error was about 30%.0%. 30%.0%.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.413-418
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• 1998

Electrical and Thermoelectric Properties of$ SbI_{3}$-doped 85% 85% $BiTe_{2}$$Se_{3}$ 단결정에서 전하 이동에 대한 살란인자는 0.1이었으며, 전자이동도와 정공이동도의 비($\mu_{e}$ /$\mu_{h}$ )는 1.45이었다. $SbI_{3}$의 첨가량이 증가할수록 전자 농도의 증가로 Seebek 계수와 전기비저항이 감소하며, Seebeck 계수와 전기비저항이 최대값을 나타내는 온도가 고온으로 이동하였다. $SbI_{3}$를 첨가한 85%$Bi_{2}$$Te_{3}$단결정에서 성능지수의 최대값은 $SbI_{3}$를 0.1 wt%첨가한 조성에서 $2.0 x 10^{-3}$ K이었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.420-421
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• 2007

본 연구에서는 유기물 발광 다이오드(OLED)의 효율을 향상시키기 위하여 버퍼층 역할을 하는 PEDOT:PSS (poly(3,4-ethylenedioxythiophene) : poly styrene sulfonate)의 공정조건을 확립하고 두께에 따른 전기적 광학적 특성을 조사하였다. PEDOT:PSS는 spin coating 방법으로 증착을 하였으며, 흘효과측정을 통하여 ITO기판과 유기버퍼층이 코팅된 기판의 전하운반체의 이동도와 전류-전압 특성을 조사하였다. 그리고 UV-vis spectrometer를 이용하여 광투과도, 굴절률, 밴드갭을 측정하였고 SEM을 이용하여 시료의 표면도 관찰하였다. 유기물 버퍼층(PEDOT:PSS)의 두께가 얇을수록 정공의 이동도가 향상됨을 알 수 있었다.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.83-90
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• 1990

The semiconducting $(Pb_1\;_xSn_x)_1$ $_yTe_y$, one of the low - temperature thermoelectric materials, has been prepared and its chemical composition and nonstoichiometry has been analyzed. The content of Pb in the specimens was determined by the complexometric back - titration method with EDTA and Pb(II) standard solutions. Te - content was analyzed with the redox titration method. The electrical conductivity and the thermoelectric power have also been measured by the DC 4 - probe and the heat-pulse technique, respectively. All of the specimens showed a nonstoichiometric behavior in their chemical compositions (Te excess), thus gave rise to a p - type semiconducting property, and the nonstoichoimetry became bigger as the Sn - content increased. The thermoelectric power vs. temperature results have been analyzed upon the basis of the Fermi level vs. temperature profiles in the saturation regime. The specimen of x=0.1 evolved a transition from p - to n - type property at about 670K, which has been explained by the fact that the mobility of electrons is bigger than that of holes in the temperature range of the intrinsic regime.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.558-567
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• 2001

본 연구에서는 알콕사이드를 전구물질로 하는 졸겔공정을 이용하여 Bi 과잉 12 mol%의 조성인 B $i_4$ $Ti_3$ $O_{12}$ 박막과 B $i_4$ $Ti_{3-x}$T $a_{x}$ $O_{12}$(x=0.1, 0.2, 0.3) 박막을 제조하였다. XPS 분석에 따르면 Ta 치환 x=0.2에서 Bi 4f의 photoemission 곡선이 낮은 결합에너지로 이동하였고 피크 강도가 감소하는 현상이 관측되었다. 이는 x=0.1과 0.2 사이에서 Bi-O 결합이 길어져 인장상태 하에 있었음을 나타내었다. B $i_4$ $Ti_3$ $O_{12}$(BIT) 박막의 유전상수와 유전손실은 100 kHz에서 340, 0.05이었고, B $i_4$ $Ti_{3-x}$T $a_{x}$ $O_{12}$ 박막에서 이들 값은 x=0.1에서 가장 높았으며, 각각 480, 0.13이었다. B $i_4$ $Ti_3$ $O_{12}$ 박막의 잔류분극과 항전계는 1.24$\mu$C/$ extrm{cm}^2$, 31.4 kV/cm 이었으나, Ta 치환 x=0.2에서 이들 값은 각각 19.7$\mu$C/$\textrm{cm}^2$, 49.5 kV/cm 에 이르렀다. 또한, B $i_4$ $Ti_3$ $O_{12}$ 박막의 누설전류 밀도는 ~$10^{-6}$ A/$\textrm{cm}^2$ 정도이었으며, Ta 치환은 누설전류를 감소시켜 Ta 치환 x=0.2 이상에서 BIT 박막에 비해 한 차수 정도 낮아졌다. Ta 치환에 따른 B $i_4$ $Ti_3$ $O_{12}$ 전기 물성에서 변화는 Bi-O 결합에서 관측된 인장상태로의 전이와 연관성이 있었으며, 덧붙여 치환에서 생성된 전자에 의한 정공보상이 이에 영향을 끼쳤다. 정공보상이 이에 영향을 끼쳤다.끼쳤다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.73.2-73.2
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• 2010

Polymer solar cells (PSCs) have attracted considerable academic and commercial interest because of their unique advantages, such as the facile manufacture of low cost, flexibility, lightweight, and solution processibility. Recently, high-performance polymer solar cells made from a mixture of poly(2,7-carbazole) derivatives, PCDTBT, and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) have been reported, with maximum power conversion efficiency of 6.1%. In this work, we report new novel copolymers based on poly(2,7-carbazole) derivatives with a suite of electron-deficient moieties or electron-rich units. We systematically investigated the synthesis, thermal stability, as well as the optical and electrochemical properties of these polymers. Detailed synthetic scheme, optical, electrochemical, and photovoltaic properties of the copolymers will be presented.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.73-73
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• 2003

최근 LCD(liquid crystal display)분야에서 고해상도와 빠른 응답속도를 가지는 다결정 실리콘 박막트랜지스터에 대한 연구를 하고 있다. 그러나, poly-Si은 poly-Sil-xGex에 비해 intrinsic carrier mobility가 낮고 고온의 결정화 공정을 필요로 한다. 따라서, Poly-Si을 대체할 재료로 poly-SiGe에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 전계에 의해 결정화가 가속되고 한쪽 방향으로 결정화를 제어하여 채널내 전자나 정공의 이동도를 향상시 킬 수 있는 새로운 결정화 방법인 전계 유도 방향성 결정화법을 이용하여 Ge 함량에 따른 a-Sil-xGex(0$\leq$x$\leq$0.5)의 결정화 특성을 연구하였다. 대기압 화학 기상 증착법으로 5000$\AA$의 산화막(SiO$_2$)이 증착된 유리 기판상에 플라즈마 화학 기상 증착법을 이용하여 800$\AA$의 비정질 실리콘을 증착한 후 RF magnetron sputtering법을 이용하여 Ge 함량에 따른 Sil-xGex 박막을 1000$\AA$ 증착하였다. Photolithograph방법을 이용하여 금속이 선택적으로 증착될 수 있는 특정 Pattern을 가진 mask를 형성한 후 금속을 DC magnetron sputtering법을 이용하여 상온에서 50$\AA$.을 증착하였다. 이후 시편에 전계를 인가하기 위해 시편의 양단에 전극을 형성한 후 DC Power Supply를 통해 전압을 제어하는 방식으로 전계를 인가하였다. 결정화 속도는 광학현미경을 이용하여 분석하였으며 결정화된 영역의 결정화 정도는 micro-Raman spectroscopy로 분석하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.44-48
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• 2008

Hole mobility characteristics of two representative biaxially strained SiGe/Si structures with high Ge contents are studied, They are single channel ($Si/Si_{1-x}Ge_x/Si$ substrate) and dual channel ($Si/Si_{1-y}Ge_y/Si_{1-x}Ge_x/Si$ substrate), where the former consists of a relaxed SiGe buffer layer with 60 % Ge content and a tensile-strained Si layer on top, and for the latter, a compressively strained SiGe layer is inserted between two layers, Owing to the hole mobility performance between a relaxed SiGe film and a compressive-strained SiGe film in the single channel and the dual channel, the hole mobility behaviors of two structures with respect to the Si cap layer thickness shows the opposite trend, Hole mobility increases with thicker Si cap layer for single channel structure, whereas it decreases with thicker Si cap layer for dual channel. This hole mobility characteristics could be easily explained by a simple capacitance model.