• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.457-458
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• 2007

We investigated a resistor network model for the horizontal AlInGaN LED. Adding the proposed current density dependent relative quantum efficiency, the power simulation can be also obtained. Comparing the simulation and the measurement results for the LED with the size of $350{\mu}m$, the model is reasonable to simulate the forward voltage and the light output power. Using this model we investigated the optimization of the position and the number of the finger electrodes in a given chip area. It shows that the center disposition of the p-finger electrode in p-area is optimal for the voltage and best for the power. And the minimum number of the n-finger electrodes is best for the power.

• Interaction and multiscale mechanics
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• v.1 no.2
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• pp.303-315
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• 2008

In this paper, thermodynamical properties of crystalline silicon under strain are calculated using classical molecular dynamics (MD) simulations based on the Tersoff interatomic potential. The Helmholtz free energy of the silicon crystal under strain is calculated by using the ensemble method developed by Frenkel and Ladd (1984). To account for quantum corrections under strain in the classical MD simulations, we propose an approach where the quantum corrections to the internal energy and the Helmholtz free energy are obtained by using the corresponding energy deviation between the classical and quantum harmonic oscillators. We calculate the variation of thermodynamic properties with temperature and strain and compare them with results obtained by using the quasi-harmonic model in the reciprocal space.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.492-499
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• 2016

Null pattern synthesis method using the Quantum-inspired Evolutionary Algorithm(QEA) is described in this study. A $12{\times}12$ planar array antenna is considered and each element of the array antenna is controlled by 6-bit phase shifter. The maximum number of iteration of 500 is used in simulation and the rotation angle for updating Q-bit individuals is determined to make the individual converge to the best solution and is summarized in a look-up table. In this study we showed that QEA can satisfactorily synthesize the null pattern using smaller number of individuals compared with the conventional Genetic Algorithm.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.630-634
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• 2016

We report the computer aided design results for a GaSb/InAs broken-gap gate all around nanowire tunneling FET (TFET). In designing, the semi-empirical tight-binding (TB) method using $sp3d5s^*$ is used as band structure model to produce the bulk properties. The calculated band structure is cooperated with open boundary conditions (OBCs) and a three-dimensional $Schr{\ddot{o}}dinger$-Poisson solver to execute quantum transport simulators. We find an device configuration for the operation voltage of 0.3 V which exhibit desired low sub-threshold swing (< 60 mV/dec) by adopting receded gate configuration while maintaining the high current characteristic ($I_{ON}$ > $100 {\mu}A/{\mu}m$) that broken-gap TFETs normally have.

• Bulletin of the Korean Chemical Society
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• v.23 no.6
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• pp.807-811
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• 2002

We present a hypothetical quantum scattering model to propose a novel electroluminescence device. Adoping with features of solid state semiconductor LED and exciplex laser, the cathode (electrol incoming potential) and anode(electron outgoing potential) are made to correspond to two 1-dimensional resonance supporting potentials, and the light emitting part to an interaction potential in the intermediate region. When an external voltage is applied, the electron flows into the cathode having small work function. Subsequently in flows via LUMO of the " electron incoming potential" loses kinetic energy emitting a photon, then continues to flow via LUMO of the "electron outgoing potential" unlike the conventional LUMO to HOMO transitions occurring in solid state semiconductor LED. In this model, the photon frequency can be controlled by adijusting the applied voltage. The model hopefully could be realized as partially conjugated hydrocarbon chains.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.607-612
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• 2007

Relationship between charge transfer mechanism and quantum coherence has been investigated using a realtime quantum dynamics approach. In the on-the-fly filtered propagator functional path integral simulation, by separating paths that belong to different mechanisms and by integrating contributions of correspondingly sorted paths, it was possible to accurately obtain quantitative contribution of different transport mechanisms. For a 5'-GAGGG-3' DNA sequence, we analyze charge transfer processes quantitatively such that the governing mechanism alters from coherent to incoherent charge transfer with respect to the friction strength arising from dissipative environments. Although the short DNA sequence requires substantially strong dissipation for completely incoherent hopping transfer mechanism, even a weak system-environment interaction markedly destroys the coherence within the quantum mechanical system and the charge transfer dynamics becomes incoherent to some degree. Based on the forward-backward path deviation analysis, the coherence variation depending on the environment is investigated numerically.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.649-654
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• 2014

In this paper, an analytical model for Surrounding Gate (SG) metal-oxide- semiconductor field effect transistors (MOSFETs) considering quantum effects is presented. To achieve this goal, we have used variational approach for solving the Poission and Schrodinger equations. This model is developed to provide an analytical expression for inversion charge distribution function for all regions of device operation. This expression is used to calculate the other important parameters like inversion charge density, threshold voltage, drain current and gate capacitance. The calculated expressions for the above parameters are simple and accurate. This paper also focuses on the gate tunneling issue associated with high dielectric constant. The validity of this model was checked for the devices with different dimensions and bias voltages. The calculated results are compared with the simulation results and they show good agreement.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1331-1346
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• 2018

Aiming at the problem that the gradient-based edge detection operators are sensitive to the noise, causing the pseudo edges, a triqubit-state measurement-based edge detection algorithm is presented in this paper. Combing the image local and global structure information, the triqubit superposition states are used to represent the pixel features, so as to locate the image edge. Our algorithm consists of three steps. Firstly, the improved partial differential method is used to smooth the defect image. Secondly, the triqubit-state is characterized by three elements of the pixel saliency, edge statistical characteristics and gray scale contrast to achieve the defect image from the gray space to the quantum space mapping. Thirdly, the edge image is outputted according to the quantum measurement, local gradient maximization and neighborhood chain code searching. Compared with other methods, the simulation experiments indicate that our algorithm has less pseudo edges and higher edge detection accuracy.

• ETRI Journal
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• v.42 no.6
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• pp.912-921
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• 2020

Quantum-dot cellular automata (QCA) is an alternative complementary metal-oxide-semiconductor (CMOS) technology that is used to implement high-speed logical circuits at the atomic or molecular scale. In this study, an optimal 2-to-4 decoder in QCA is presented. The proposed QCA decoder is designed using a new formulation based on the MV32 gate. Notably, the MV32 gate has three inputs and two outputs, which is equivalent two 3-input majority gates, and operates based on cellular interactions. A multilayer design is suggested for the proposed decoder. Subsequently, a new and efficient 3-to-8 QCA decoder architecture is presented using the proposed 2-to-4 QCA decoder. The simulation results of the QCADesigner 2.0.3 software show that the proposed decoders perform well. Comparisons show that the proposed 2-to-4 QCA decoder is superior to the previously proposed ones in terms of cell count, occupied area, and delay.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.3
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• pp.1-6
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• 2010

A comparative analysis of quantum-mechanical and classical simulation regarding corner effect in a Saddle MOSFET has been carried out using a 3-D numerical simulator. The comparison has shown that quantum simulation gives correct description of device by providing accurate peak E-density position and magnitude at the Si-fin cross-section, hence accurate analysis of corner effect and its impact on device threshold voltage (Vth) characteristics is carried out. Moreover, rounding the Si-fin comers or lowering the body doping have been shown as two possible techniques to suppress the undesirable corner effect.