• Applied Science and Convergence Technology
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• v.23 no.3
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• pp.128-133
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• 2014

We study the ballistic spin transport properties in a two-dimensional electron gas system in the presence of magnetic barriers using a transfer matrix method. We concentrate on the size-effect of the magnetic barriers parallel to a two-dimensional electron gas plane. We calculate the transmission probability of the ballistic spin transport in the magnetic barrier structure while varying the width of the magnetic barriers. It is shown that resonant tunneling oscillation is affected by the width and height of the magnetic barriers sensitively as well as by the inter-spacing of the barriers. We also consider the effect of additional electrostatic modulation on the top of the magnetic barriers, which could enhance the current spin polarization. Because all-semiconductor-based devices are free from the resistance mismatch problem, a resonant tunneling structure using the two-dimensional electron gas system with electric-magnetic modulation would play an important role in future spintronics applications. From the results here, we provide information on the physical parameters of a device to produce well-defined spin-polarized current.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.299-304
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• 2016

2차원 반도체 소재의 경우 물질종류마다 내포하고 있는 고유결함에 의해서 Fermi-Level Pinning 이 발생하여 이로 인한 Schottky Barrier transistor로 동작을 하게 되며, 이는 접합부에 Carrier Injection 정도와 Schottky Barrier을 통과하는 Tunneling 정도에 의해서 소자의 특성이 결정 된다. 본 연구에서는 시뮬레이션을 통하여 2차원 반도체인 $MoS_2$소자를 설계하고, S/D Doping에 따라 접촉 저항 개선 효과와 소자의 동작특성이 어떠한 영향을 미치는지 연구하여 최대 $250cm^2/V{\cdot}sec$의 field effect mobility 의 결과를 얻었다. 또한 S/D doping 에 따라 각 저항 성분의 영향을 분석하였으며 면저항 및 접촉 저항 둘 다 doping 농도가 증가함에 따라 감소하는 결과를 나타내며, S/D doping의 영향은 접촉저항에서 더 크게 나타났다. 더불어 2차원 반도체의 Resistance network model 을 제안하여 subthreshold 영역에서는 $R_{ic}$, saturation 영역에서는 $R_{ish}$ 가 전체저항에서 주요한 변수로 전체저항식에 포함되어야 한다는 것을 시뮬레이션을 통해서 검증하였다.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.513-515
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• 2016

There are various walking devices based on Theo Jansen mechanism. And these systems controlled by complicate equations. So we decided to optimize the design of walking device with two points of view. The device is required to ensure stability while maintaining the high speed. To simplify the control system, we applied trigonometric ratio with ideal Jansen trajectory. As a result, we were able to draw the connection between height of barrier and Ground Length (GL). Also we could change traveling distance and Ground Angle Coefficient (GAC) by shifting the position of the joints. Through controlling these parameter, we can analyze stability and speed of the device. Ultimately, we develop the device that can walk more efficiently by the optimization process.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.149-158
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• 1999

The modern trends of optical storage devices can be characterized by high density in information recording, and high bandwidth in data input/output processing rate. These make servo engineers to face with a new barrier on control system design in much more difficult way. The first step to attack this barrier will be through a systematic modeling for the dynamic characteristics of optical storage drive. in this paper, an analytical dynamic model for an optical storage drive based on FEM is drived, and compared with experimental results. Through this comparison, a practical dynamic model on the focusing and tracking motion of optical storage drive is proposed for the initiation of real control system design problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.200-203
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• 2007

Devices of junction barrier schottky(JBS) structure using 4H-SiC substrates with wide energy band gaps was designed and fabricated. As a measurement results, the device of reverse I-V characteristics was shown as more than 1000 V, its design optimum length of p-grid was $3{\mu}m$ space. In this paper, I-V characteristics was modeled by using of device fabricated process conditions parameters and it was extracted that the I-V property parameters, and it was compared and analyzed with between device parameters and model parameters.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.7
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• pp.388-393
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• 2000

Hydrogen-sensing behaviors of Pd- and Pt-SiC Schottky diodes, fabricated on the same SiC substrate, have been systematically compared and analyzed as a function of hydrogen concentration and temperature by I-V and$\DeltaI-t$ methods under steady-state and transient conditions. The effects of hydrogen adsorption on the device parameters such as the barrier height are investigated. The significant differences in their hydrogen sensing characteristics have been examined in terms of sensitivity limit, linearity of response, response rate, and response time. For the investigated temperature range, Pd-SiC Schottky diode shows better performance for H2 detection than Pt-SiC Schottky diode under the same testing conditions. The physical and chemical mechanisms responsible for hydrogen detection are discussed. Analysis of the steady-state reaction kinetics using I-V method confirmed that the atomistic hydrogen process is responsible for the barrier height change in the diodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.2
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• pp.71-77
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• 1982

This poper proposes the method of the balanced-mixer realization in the X-Band frequency range by the MIC coplanar magic-tee. This magic-tee is composed with microstrip and slot, as suggested by Ronde. The characteristics of balancing and isolation in this magic-tee is more preferable to those of the rat-race or hybrid ring in the wide frequency range. So, experimentally in this paper the characteristics of the MIC balanced-mixed are obtained with the VSWR less than 1, 2(in Local and Signal Arms) and the Conversion Loss, 6 dB in that frequency range, when the mixer is designed in the 3rd order (in E-arm) and 2nd order(in H-arm) Chebyshev matching networks, and with two symmetrical Schottkey Barrier Diodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.729-732
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• 2006

This paper proposes and implements consistency algorithm that is serviced streaming data efficiently in VOD system. The media data is loaded into each node by Round Robin method. The barrier mechanism is changed into the minimum data factor(SH. GOP) of media data in this paper. In addition in order to fast media data service, the additional features are implemented in the consistency algorithm. Additional feature of the consistency algorithm is added. First, time synchronization algorithm is added the suggested consistency algorithm. Second, the prepaging mechanism supports efficient buffering service. I experimented the suggested consistency algorithm on two DSM systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.405-408
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• 1998

In this paper, We analyzed the current-voltage characteristics with n-type silicon substrates concentration and temperature variations (Room temperature, 5$0^{\circ}C$, 75$^{\circ}C$) in platinum silicide and silicon junction. Measurement electrical parameters are forward turn-on voltage, reverse breakdown voltage, barrier height, saturation current, ideality factor, dynamic resistance acceding to junction concentration of substrates and temperature variations. As a result, the forward turn-on voltage, reverse breakdown voltage, barrier height and dynamic resistance were decreased but saturation current and ideality factor were increased by substrates concentration variations. Reverse breakdown voltage and dynamic resistance were increased by temperature variations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2247-2252
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• 2008

The SiOC films as the carbon doped silicon oxide film were prepared with the variation of flow rater ratios by plasma enhanced chemical vapor deposition. The samples were analyzed by the fourier transform infrared spectroscopy, I-V measurement and scanning electron microscopy. The samples were shown the chemical shift according to the flow rate ratios, and the grain did not formed at the sample with hybrid properties. The leakage currents decreased according to the increasing of the substrate temperature at the sample with hybrid properties, but the potential barrier increased.