• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.203-206
• /
• 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.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.379-382
• /
• 1997

We present a hybrid self-tuning method using hyper elliptic Gaussian membership function. The proposed method applies a GA to identify the structure and the parameters of a fuzzy inference system. The parameters obtained by a GA, however, are near optimal solutions. So we solve this problem through a backpropagation-type gradient method. It is called GA hybrid self-tuning method in this paper. We provide a numerical example to evaluate the advantage and effectiveness of the proposed approach and compare with the conventional method.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1564-1567
• /
• 2009

Cu(In,Ga)$Se_2$ (CIGS) thin films were formed using CIGS bulk by electron-beam evaporation method with an evaporation current from 20 mA to 90 mA. The experimental results showed that the chemical compositions and the properties of CIGS films varied with the different evaporation current. The Cu-rich CIGS film was deposited successfully with a band gap of 1.20 eV when the evaporation current was 90 mA.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1216-1218
• /
• 1996

Genetic algorithm(GA) is useful to find optimal solution without any special mathematical modeling. This study presents to search optimal path of Autonomous Mobile Robot(AMR) by using GA without encoding and decoding procedure. Therefore, this paper shows that the proposed algorithm using GA can reduce the computation time to search the optimal path.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.04a
• /
• pp.1054-1056
• /
• 2011

플라스틱 시설원예는 자본과 시설이 요구되지만 제철이 아닐 때도 생산을 통해 생산자의 소득 증대에 기여하고 이는 생산자가 보다 높은 품질의 작물을 생산하는 유인이 된다. 이를 위해서는 재배되는 작물에 최적화된 생육환경을 제공해줄 필요가 있으며 현재까지의 생장데이터를 이용하여 미래의 생장상태를 예측하고, 부족한 부분을 보완해줄 필요가 있다. 본 논문에서는 토마토를 대상으로 플라스틱 시설원예 환경에서의 예측시스템을 설계한다. 동일한 토마토이지만 품종에 따라 생육환경이나 예측모델이 달라질 수 있으므로 다양한 예측모델이 필요에 따라 로딩되어 사용될 수 있도록 한다.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.6
• /
• pp.820-832
• /
• 1986

In contrast to conventional liquid phase epitaxy of GaAs, surface kinetics limited growth is predominant in selective liquid phase epitaxy. For the stripe openings in the high-index crystal-lographic directions, the well-known facet formations and the decompositions into the low index planes or smooth circular surfaces are observed depending on the growth kinetics. For the low index direction stripe, surface kinetics limited growth is evident. By a numerical calcualtion we show that these phenomena are due to the enhanced masstransport by two dimensional diffusion and growth rate anisotropy which is found to be very stdrong with cusped minima for some singular planes in the solution growth as well as in vapor phase epitaxy. Morphological stability is briefly treated in terms of diffusion and its implications on device application are stated. Tese phenomena may be common to III-V compound semiconductors as well as GaAs.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.6
• /
• pp.780-788
• /
• 1986

1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.

• Journal of the Korean Magnetics Society
• /
• v.23 no.4
• /
• pp.117-121
• /
• 2013

In this study we investigated magnetism and magnetostriction of B2-structured FeX (X = Al, Si, Ni, Ga, Ge, and Sn) using a first-principles method, in order to survey the possibility of developing a transition metal based magnetostriction material. The Full-potential Linearized Augmented Plane Wave method was employed for solving the Kohn-Sham equation within the generalized gradient approximation for exchange-correlation interaction between electrons. FeX alloys are stabilized in ferromagnetic states except for the FeSi and FeGe alloys. Magnetostrcition coefficients of FeX (X = Al, Ni, Ga, and Sn) were calculated to be -5, +6, -84, -522ppm, respectively. It is noteworthy that the magnetostriction coefficient (-522ppm) of FeSn is larger than that (+400ppm) of Gafenol.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.261-262
• /
• 2007

In this study we present the effect of annealing temperatures on the structural, electrical and optical characteristics of Ga-doped ZnO(GZO) films. GZO target have been deposited on corning 7059 glass substrates by DC sputtering. GZO films were annealed at temperatures of 400, 500, $600^{\circ}C$ in air ambient for 20 min. Experimental resulted in as-grown film shows the resistivity of $6{\times}10^{-1}\;{\Omega}{\cdot}cm$ and transmittance under 85%, whereas the electrical and optical properties of film annealed at $500^{\circ}C$ are enhanced up to $1.9{\times}10^{-3}\;{\Omega}{\cdot}cm$ and 90%, respectively.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.2
• /
• pp.223-229
• /
• 2017

This paper analyzes the effect of a dual-metal-gate structure on the electrical characteristics of AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors. These structures have two gate metals of different work function values (${\Phi}$), with the metal of higher ${\Phi}$ in the source-side gate, and the metal of lower ${\Phi}$ in the drain-side gate. As a result of the different ${\Phi}$ values of the gate metals in this structure, both the electric field and electron velocity in the channel become better distributed. For this reason, the transconductance, current collapse phenomenon, breakdown voltage, and radio frequency characteristics are improved. In this work, the devices were designed and analyzed using a 2D technology computer-aided design simulation tool.