• 제목/요약/키워드: device physics

검색결과 719건 처리시간 0.028초

Investigating the effect of changing parameters in the IEC device in comparative study

  • H. Ghammas;M.N. Nasrabadi
    • Nuclear Engineering and Technology
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    • 제56권1호
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    • pp.292-300
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    • 2024
  • Kinetic simulations have been performed on an Inertial Electrostatic Confinement Fusion (IECF) device. These simulations were performed using the particle-in-cell (PIC) method to analyze the behavior of ions in an IEC device and the effects of some parameters on the Confinement Time (CT). CT is an essential factor that significantly contributes to the IEC's performance as a nuclear fusion device. Using the PIC method, the geometry of a two-grided device with variable grid radius, the number of cathode grid rings, variable pressure and different dielectric thickness for the feed stalk was simulated. In this research, with the development of previous works, the interaction of particles was simulated and compared with previous results. The simulation results are in good agreement with the previous results. In these simulations, it was found that with the increase of the dielectric thickness of the feed stalk, the electric field was weakened and as a result, the confinement time was reduced. On the other hand, with the increase of the cathode radius, the confinement time increased. Using the results, an IEC device can be designed with higher efficiency and more optimal CT for ions.

고집적 소자에 적용되는 저저항 텅스텐 박막에서 응력의 RF power 의존성 (RF Power Dependence of Stresses in Plasma Deposited Low Resistive Tungsten Films for VLSI Devices)

  • 이창우;고민경;오환원;우상록;윤성로;김용태;박영균;고석중
    • 한국재료학회지
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    • 제8권11호
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    • pp.977-981
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    • 1998
  • Si 기판의 온도를 200에서 $500^{\circ}C$까지 변화시켜가면서 고집저 소자의 금속배선으로 응용되고 있는 저저항의 텅스텐 박막을 플라즈마 화학증착 방법에 의해 제작하였다. 이렇게 증착된 텅스텐 박막의 비저항은 $H_2/WF_6 $ 가스의 분압비에 따라 매우 민감하게 작용하는 것을 알 수있다. 플라즈마 밀도가 $0.7W/\textrm{cm}^2$ 이하에서는 박막내에 존재하는 잔류응력이 $2.4\times10^9dyne/\textrm{cm}^2$ 이하이다. 그러나 1.8에서 $2.7W/\textrm{cm}^2$로 증가함에 따라 잔류응력은 $8.1\times10^9$에서 $1.24\times10^{10}dyne/\textrm{cm}^2$로 갑자기 증가하는데 이는 박막을 증착할 때에 플라즈마 밀도가 증가하면 이온이나 radical bombardment 의 영향 때문이다.

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Polymer Light-Emitting Diodes with Efficient Energy Transfer in Fluorene-Based Copolymer Systems

  • Kim, Jin-Young;Park, Sung-Heum;Park, Hye-Jin;Jin, Sung-Ho;Lee, Kwang-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1060-1061
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    • 2003
  • We report photo- (PL), and electroluminescence (EL) realized via intrachain and interchain energy transfer in poly[9,9-(2'-octyl)fluorene-2,7-vinylene]-co-poly[2-methoxy,5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene] (PFV-co-MEH-PPV) copolymer systems. Energy transfer begins even at the device using 5 % MEH-PPV copolymer, and shows the best device performance for the 10 % MEH-PPV copolymer.

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Design and Construction of an HTS DC SQUID Electronic Gradiometer NDE system

  • Kim, J.Y.;Han, S.G.;Kang, J.H.;Lee, E.H.;Song, I.H.
    • Progress in Superconductivity
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    • 제1권2호
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    • pp.115-119
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    • 2000
  • We designed and constructed a non-destructive evaluation system using an HTS DC SQUID electronic gradiometer. Our DC SQUID electronic gradiometer is composed of two DC SQUID magnetometers. The system included a non-magnetic stainless steel cryostat and a set of coaxial exciting coils, which were used to induce an eddy current in the test piece. We also have calculated the eddy current density produced by an exciting coil in any direction of the testing object. We could compute the eddy current density distribution in 3D. The SQUIDs were computer controlled and the output data from the electronic gradiometer was obtained by using a Labview software.

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A Privacy-protection Device Using a Directional Backlight and Facial Recognition

  • Lee, Hyeontaek;Kim, Hyunsoo;Choi, Hee-Jin
    • Current Optics and Photonics
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    • 제4권5호
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    • pp.421-427
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    • 2020
  • A novel privacy-protection device to prevent visual hacking is realized by using a directional backlight and facial recognition. The proposed method is able to overcome the limitations of previous privacy-protection methods that simply restrict the viewing angle to a narrow range. The accuracy of user tracking is accomplished by the combination of a time-of-flight sensor and facial recognition with no restriction of detection range. In addition, an experimental demonstration is provided to verify the proposed scheme.

Inverted structure perovskite solar cells: A theoretical study

  • Sahu, Anurag;Dixit, Ambesh
    • Current Applied Physics
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    • 제18권12호
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    • pp.1583-1591
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    • 2018
  • We analysed perovskite $CH_3NH_3PbI_{3-x}Cl_x$ inverted planer structure solar cell with nickel oxide (NiO) and spiroMeOTAD as hole conductors. This structure is free from electron transport layer. The thickness is optimized for NiO and spiro-MeOTAD hole conducting materials and the devices do not exhibit any significant variation for both hole transport materials. The back metal contact work function is varied for NiO hole conductor and observed that Ni and Co metals may be suitable back contacts for efficient carrier dynamics. The solar photovoltaic response showed a linear decrease in efficiency with increasing temperature. The electron affinity and band gap of transparent conducting oxide and NiO layers are varied to understand their impact on conduction and valence band offsets. A range of suitable band gap and electron affinity values are found essential for efficient device performance.

Integer and fractional quantum Hall effect in graphene heterostructure

  • Youngwook Kim
    • 한국초전도ㆍ저온공학회논문지
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    • 제25권1호
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    • pp.1-5
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    • 2023
  • The study of two-dimensional electron systems with extraordinarily low levels of disorder was, for a long time, the exclusive privilege of the epitaxial thin film research community. However, the successful isolation of graphene by mechanical exfoliation has truly disrupted this field. Furthermore, the assembly of heterostructures consisting of several layers of different 2D materials in arbitrary order by exploiting van der Waals forces has been a game-changer in the field of low-dimensional physics. This technique can be generalized to the large class of strictly 2D materials and offers unprecedented parameters to play with in order to tune electronic and other properties. It has led to a paradigm shift in the field of 2D condensed matter physics with bright prospects. In this review article, we discuss three device fabrication techniques towards high mobility devices: suspended structures, dry transfer, and pick-up transfer methods. We also address state-of-the-art device structures, which are fabricated by the van der Waals pick-up transfer method. Finally, we briefly introduce correlated ground states in the fractional quantum Hall regime.

Novel Punch-through Diode Triggered SCR for Low Voltage ESD Protection Applications

  • Bouangeune, Daoheung;Vilathong, Sengchanh;Cho, Deok-Ho;Shim, Kyu-Hwan;Leem, See-Jong;Choi, Chel-Jong
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제14권6호
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    • pp.797-801
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    • 2014
  • This research presented the concept of employing the punch-through diode triggered SCRs (PTTSCR) for low voltage ESD applications such as transient voltage suppression (TVS) devices. In order to demonstrate the better electrical properties, various traditional ESD protection devices, including a silicon controlled rectifier (SCR) and Zener diode, were simulated and analyzed by using the TCAD simulation software. The simulation result demonstrates that the novel PTTSCR device has better performance in responding to ESD properties, including DC dynamic resistance and capacitance, compared to SCR and Zener diode. Furthermore, the proposed PTTSCR device has a low reverse leakage current that is below $10^{-12}$ A, a low capacitance of $0.07fF/mm^2$, and low triggering voltage of 8.5 V at $5.6{\times}10^{-5}$ A. The typical properties couple with the holding voltage of 4.8 V, while the novel PTTSCR device is compatible for protecting the low voltage, high speed ESD protection applications. It proves to be good candidates as ultra-low capacitance TVS devices.