• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.281-281
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• 2009

Electrical analysis of red, green and blue (RGB) organic light emitting diode (OLED), which were measured at various temperatures from 230K to 370K by steps of 20K, were investigated using current-voltage(I-V) characteristics. Ideality factor and series resistance were obtained from the thermionic emission theory. Experimental results showed that the ideality factors were 2.12 for red, 3.80 for green, and 6.03 for blue OLED at 290K, respectively. The series resistance were 1960, 2190, 2630$\Omega$ for red, green and blue OLED at the same temperature. It was found that the OLED ideality factors were much higher than near unity for well-behaved silicon diodes, because of the organic material and multi-layer fabrication diode. In addition, the series resistance was near 2k$\Omega$ range. More researches are required to reduce both ideality factors and series resistance to increase the efficiency of OLEDs.

• Transactions on Electrical and Electronic Materials
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• 제15권6호
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• pp.324-327
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• 2014

Germanium (Ge) is a promising material for next generation nanoelectronics and multiple junction solar cells. This work investigated the electrical properties in Cu/p-type Ge Schottky diodes, using current-voltage (I-V) measurements. The Schottky barrier heights were 0.66, 0.59, and 0.70 eV from the forward ln(I)-V, Cheung, and Norde methods, respectively. The ideality factors were 1.92 and 1.78 from the forward ln(I)-V method and Cheung method, respectively. Such high ideality factor could be associated with the presence of an interfacial layer and interface states at the Cu/p-Ge interface. The reverse-biased current transport was dominated by the Poole-Frenkel emission rather than the Schottky emission.

• 센서학회지
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• 제5권5호
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• pp.1-10
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• 1996

EFG Si 태양전지를 전류-전압, 표면광전압, 전자빔유도_전류, 전자미세프로브, 전자역산란의 여러 가지 기술을 이용하여 분석하였다. 전류-전압 그래프를 여러 온도에서 측정한 결과 EFG-Si 태양전지는 전압에 따라 변하는 shunt 저항을 가진 것이 밝혀졌다. 이러한 shunt 저항은 precipitate와 grain boundary에 의해 생긴 것으로 공간전하영역 내의 불순물 에너지 준위로 tunneling에 의해 이동한 캐리어의 재결합으로 일어난 결과이다. 전류-전압 과 표면광전압 기술을 결합하면 태양전지의 pn접합과 기판 (substrate)을 동시에 분석할 수 있다. Diode ideality factor와 표면 광전압은 Pn접합의 특성을, 소수캐리어 확산거리는 substrate특성을 표시한다. EFG 태양 전지를 분석한 결과, 전압에 따라 변하는 shunt 저항은 효율에 따라 정도 차이는 있지만 모든 시편에서 발견되며, 태양전지의 성능을 저하시키는 중요한 원인 중의 하나가 된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.457-457
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• 2013

Current-voltage (I-V) measurements of crystalline silicon solar cells was conducted under dark conditions with the temperature range of 260 K~350 K. Using the calculation method, we extracted the crucial factors of ideality factor (n) and activation energy (Ea) to investigate the carrier conducting path in the space charge region (SCR) and the quasi-neutral region (QNR). Values of n were decreased with increasing temperature in both SCR and QNR. We also conformed that the value of Ea of SCR was larger than that of QNR about 0.4 eV. The temperature dependence of n indicates that the carrier conducting path is dominated by carrier recombination-generation in the SCR region than in the QNR region.

• Current Photovoltaic Research
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• 제2권2호
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• pp.69-72
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• 2014

We investigated current-voltage (I-V) and capacitance (C)-V characteristics of solution-processed thin film solar cells, consisting of $Cu(In,Ga)S_2$ and $CuInS_2$ stacked absorber layers. The ideality factors, extracted from the temperature-dependent I-V curves, showed that the tunneling-mediated interface recombination was dominant in the cells. Rapid increase of both series- and shunt-resistance at low temperatures would limit the performance of the cells, requiring further optimization. The C-V data revealed that the carrier concentration of the $CuInS_2$ layer was about 10 times larger than that of the $Cu(In,Ga)S_2$ layer. All these results could help us to find strategies to improve the efficiency of the solution-processed thin film solar cells.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.203-206
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• 1987

$Ga_{1-x}Al_xAs$ solar cells have been fabricated by LPE and characterized as a function of operating temperature from $25^{\circ}C$ to $l30^{\circ}C$. Open circuit voltage decreases linearly with increasing temperature by $1.4mv/^{\circ}C$, while degradation of silicon solar cells is about $2.2-2.5\;mv/^{\circ}C$. Experimental results regarding to GaAS solar cells, such as saturation current, ideality factors and fill factors are characterized as a function of operating temperature.

• 반도체디스플레이기술학회지
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• 제14권1호
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• pp.27-30
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• 2015

SiC based Schottky barrier diodes were prepared by using the facing targets sputtering method. In this research, 4H-SiC polytypes of SiC were adopted and Molybdenum, Titanium was employed as the Schottky metal of the metal-semiconductor contacts. Both structures showed the rectifying nature in their forward and reverse J-V characteristic curve and the ideality factors calculated from these plots that were close to unity were represented the nearly ideal behavior. Difference of Schottky barrier height between prepared devices was also corresponding with the electrical characteristics of themselves. Therefore the suitability of the facing targets sputtering method for fabrication of Schottky diodes could be suggested from these results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.600-600
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• 2013

We have fabricated Cr nanodot Schottky diodes utilizing AAO templates formed on n-Si substrates. Three different sizes of Cr nanodots (about 75.0, 57.6, and 35.8 nm) were obtained by controlling the height of the AAO template. Cr nanodot Schottky diodes showed a rectifying behavior with low SBHs of 0.17~0.20 eV and high ideality factors of 5.6~9.2 compared to those for the bulk diode. Also, Cr nanodot Schottky diodes with smaller diameters yield higher current densities than those with larger diameters. These electrical behaviors can be explained by both Schottky barrier height (SBH) lowering effects and enhanced tunneling current due to the nanoscale size of the Schottky contact. Also, we have fabricated Cr-Si nanorod Schottky diodes with three different lengths (130, 220, and 330 nm) by dry etching of n-Si substrate. Cr-Si nanorod Schottky diodes with longer nanorods yield higher reverse current than those with shorter nanorods due to the enhanced electric field, which is attributed to a high aspect ratio of Si nanorod.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.461-464
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• 1998

Self-aligned AlGaAs/GaAs HBTs with the emitter area of 1.5*10.mu.$m^{2}$ were fabricated usng $WN_{x}$ as emitter metal. Their DC and RF characteristics were investigated. The common emitter current gain was 45 at $J_{c}$ = 6*$10^{4}$A/$cm^{2}$. From the Gummel plot, the ideality factors of $I_{c}$ and $I_{B}$ were 1.18 and 1.70, respectively. Emitter and base resistance were extracted from voltage drop region in gummel plot, and their values were 5.3.ohm. and 38.2.ohm.. The extrapolated $f_{T}$ = 72GHz and $f_{max}$ = 81GHz were obtained at $V_{CE}$ = 2V.

• 전자공학회논문지A
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• 제32A권1호
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• pp.129-137
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• 1995

AlGaAs/GaAs HBTs have been fabricated using SABM (Self-Aligned Base Metal) process technique. The mesa type HBTs were fabricated through following steps: isolation implant, wet etching, metal lift-off, and airbridge interconnection process. The fabricated HBTs with 2umx10um size emitter showed a common emitter current gain of 10 at a collector current density of Jk=100kA/cm$^{2}$, a breakdown volgate BVCEO of 8V, and the ideality factors of base and collector junctions of 1.6 and 1.1, respectively. On-wafer S-Parameter measurement at 0.5~18GHz has been made for the characterization of the common emitter HBTx with a 2umx10um size emitter. The extrapolated current gain cut-off frequency of ft=30GHz and maximum oscillation frequency of fmax=23 GHz were obtained at a collector current density of Jc=70kA/cm$^{2}$. Small signal HBT equivalent circuit was extracted from the S-Parameter data.