• Title/Summary/Keyword: Layer Thickness

Search Result 5,200, Processing Time 0.032 seconds

Design of Thin RC Absorbers Using a Silver Nanowire Resistive Screen

  • Lee, Junho;Lee, Bomson
    • Journal of electromagnetic engineering and science
    • /
    • v.16 no.2
    • /
    • pp.106-111
    • /
    • 2016
  • A resistive and capacitive (RC) microwave absorber with a layer thickness less than a quarter of a wavelength is investigated based on closed-form design equations, which are derived from the equivalent circuit of the RC absorber. The RC absorber is shown to have a theoretical 90% absorption bandwidth of 93% when the electrical layer thickness is 57 (about λ0/6). The trade-offs between the layer thickness and the absorption bandwidth are also elucidated. The presented formulation is validated by a design example at 3 GHz. The RC absorber is realized using a silver nanowire resistive rectangular structure with surrounding gaps. The measured 90% absorption bandwidth with a layer thickness of λ0/8 is 76% from 2.3 GHz to 5.1 GHz in accordance with the theory and EM simulations. The presented design methodology is scalable to other frequencies.

Study of OLED luminescence efficiency by electron Injection layer change (유기발광 소자의 전자 주입층 두께 변화에 따른 발광효율 연구)

  • Lee, Jung-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.11a
    • /
    • pp.555-558
    • /
    • 2004
  • The efficiency of electron injection from the cathode is strongly dependent on the thickness of the LiF buffer-layer. We used LiF to electron Injection layer. We compared characteristics of organic light emitting device changing LiF thin film thickness from 1.0 m to 10.0 nm. Experiment result, we found that LiF thickness has the optimized electrical characteristics in 3.0 m. In this paper, we did research about electrical characteristics of organic light emitting device by LiF thickness change using method numerical analysis method. We proved adequate experimental results that compare results of numerical analysis, and come out through an experiment results is validity.

  • PDF

Influence of Ag thickness on properties of AZO/Ag/AZO Multi-layer Thin Films (AZO/Ag/AZO 다층박막의 Ag두께에 따른 특성 연구)

  • Yeon, Je ho;Kim, Hong Bae
    • Journal of the Semiconductor & Display Technology
    • /
    • v.16 no.2
    • /
    • pp.27-31
    • /
    • 2017
  • AZO/Ag/AZO multi-layer films deposited on glass substrate by RF magnetron sputtering and thermal evaporator have a much better electrical properties than Al-doped ZnO thin films. The multi-layer structure consisted of three layers, AZO/Ag/AZO, the electrical and optical properties of AZO/Ag/AZO were changed mainly by thickness of Ag layers. The optimum thickness of Ag layers was determined to be 90\AA for high optical transmittance and good electrical conductivity. The Ag layers thickness 90\AA is an optical transmittance greater than 80% of visible light and the obtained multilayer thin film with the low resistivity of 8.05×103Ωcm and the low sheet resistance 5.331Ω/sq. Applying to TCO and Solar electrode will improve efficiency.

  • PDF

Optimum thickness of GaAs top layer in AlGaAs-based 850 nm VCSELs for 56 Gb/s PAM-4 applications

  • Yu, Shin-Wook;Kim, Sang-Bae
    • ETRI Journal
    • /
    • v.43 no.5
    • /
    • pp.923-931
    • /
    • 2021
  • We studied the influence of GaAs top-layer thickness on the small-signal modulation response and 56 Gb/s four-level pulse-amplitude modulation eye quality of 850 nm vertical-cavity surface-emitting lasers (VCSELs). We considered the proportionality of the gain-saturation coefficient to the photon lifetime. The simulation results that employed the transfer-matrix method and laser rate equations led to the conclusion that the proportionality should be considered for proper explanation of the experimental results. From the obtained optical eyes, we could determine an optimum thickness of the GaAs top layer that rendered the best eye quality of VCSEL. We also compared two results: one result with a fixed gain-saturation coefficient and the other that considered the proportionality. The former result with the constant gain-saturation coefficient demonstrated a better eye quality and a wider optimum range of the GaAs top-layer thickness because the resultant higher damping reduced the relaxation oscillation.

Magnetic field distribution in steel objects with different properties of hardened layer

  • Byzov, A.V.;Ksenofontov, D.G.;Kostin, V.N.;Vasilenko, O.N.
    • Advances in Computational Design
    • /
    • v.7 no.1
    • /
    • pp.57-68
    • /
    • 2022
  • A simulation study of the distribution of magnetic flux induced by a U-shaped electromagnet into a two-layer massive object with variations in the depth and properties of the surface layer has been carried out. It has been established that the hardened surface layer "pushes" the magnetic flux into the bulk of the magnetized object and the magnetic flux penetration depth monotonically increases with increasing thickness of the hardened layer. A change in the thickness and magnetic properties of the surface layer leads to a redistribution of magnetic fluxes passing between the poles of the electromagnet along with the layer and the bulk of the steel object. In this case, the change in the layer thickness significantly affects the magnitude of the tangential component of the field on the surface of the object in the interpolar space, and the change in the properties of the layer affects the magnitude of the magnetic flux in the magnetic "transducer-object" circuit. This difference in magnetic parameters can be used for selective testing of the surface hardening quality. It has been shown that the hardened layer pushes the magnetic flux into the depth of the magnetized object. The nominal depth of penetration of the flow monotonically increases with an increase in the thickness of the hardened layer.

Characteristics and Stability of Compositional Convection in Binary Solidification with a Constant Solidification Velocity (일정한 응고속도를 갖는 2성분 응고에서 조성 대류의 특성 및 안정성)

  • Hwang, In Gook
    • Korean Chemical Engineering Research
    • /
    • v.52 no.2
    • /
    • pp.199-204
    • /
    • 2014
  • In binary solidification compositional convection in a porous mushy layer influences the quality of the final products. We consider the mushy layer solidifying from below with a constant solidification velocity. The disturbance equations for the mushy layer are derived using linear stability theory. The basic-state temperature fields and the distribution of the porosity in the mushy layer are investigated numerically. When the superheat is large, the thickness of the mushy layer is relatively small compared to the thickness of the thermal boundary layer. With decreasing the superheat the critical Rayleigh number based on the thickness of the mushy layer increases and the mushy layer becomes stable to the compositional convection. The critical Rayleigh number obtained from the continuity conditions of temperature and heat flux at the mush-liquid interface is smaller than that from the isothermal condition at the upper boundary of the mushy layer.

The Influence of AlN Buffer Layer Thickness on the Growth of GaN on a Si(111) Substrate with an Ultrathin Al Layer

  • Kwon, Hae-Yong;Moon, Jin-Young;Bae, Min-Kun;Yi, Sam-Nyung;Shin, Dae-Hyun
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.32 no.3
    • /
    • pp.461-467
    • /
    • 2008
  • It was studied the effect of a pre-deposited ultrathin Al layer as part of a buffer layer for the growth of GaN. AlN buffer layers were deposited on a Si(111) substrate using an RF sputtering technique, followed by GaN using hydride vapor phase epitaxy (HVPE). Several atomic layers of Al were deposited prior to AlN sputtering and the samples were compared with the others grown without pre-deposition of Al. And it was also studied the influence of AlN buffer layer thickness on the growth of GaN. The peak wavelength of the photoluminescence (PL) was varied with increasing the thickness of the GaN and AlN layers. The optimum thickness of AlN on a Si(111) substrate with an ultrathin Al layer was about 260\AA. Scanning electron microscope (SEM) images showed coalescent surface morphology and X-ray diffraction (XRD) showed a strongly oriented GaN(0002) peak.

Electrical and Optical Properties of Semitransparent Metal Electrodes for Top-emission Organic Light-emitting Diodes (전면 발광 유기 발광 소자용 반투명 금속의 전기적 및 광학적 특성)

  • Shin, Eun-Chul;An, Hui-Chul;Kim, Tae-Wan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.21 no.10
    • /
    • pp.938-942
    • /
    • 2008
  • Electrical and optical properties of semitransparent Ag and Al layer were studied, which are used for the electrodes in top-emission organic light-emitting diodes. Sheet resistance and transmittance of visible light through a thin layer were measured and analyzed. Several thin metal layers of Ag and Al were deposited onto a glass substrate up to a thickness of 50 nm using a thermal evaporation. Sheet resistance measurements show that a layer thickness is needed more than 15 nm and 20 nm for Ag and Al, respectively, when a proper sheet resistance is assumed to be less than 50Ω/sq. From the measurements of transmittance of visible light through a thin-metal layer, metallic behavior was observed when the layer thickness is over 25 nm for both films. Thus, from a study of sheet resistance and transmittance of visible light, a minimum proper thickness of semitransparent metal layer is 20 nm and 25 nm for Ag and Al, respectively.

Efficiency Improvement of Organic Light-emitting Diodes depending on the Thickness Variation of BCP using Electron Transport Layer (전자 수송층 BCP의 두께변환에 따른 유기발광소자 효율 개선)

  • Kim, Weon-Jong;Shin, Hyun-Teak;Hong, Jin-Woong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.22 no.4
    • /
    • pp.327-332
    • /
    • 2009
  • In the devices structure of ITO/N,N'-diphenyl-N,N' bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) /tris (8-hydroxyquinoline)aluminum(Alq3)electron-transport-layer(ETL)(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP))/Al, we have studied the efficiency improvement of organic light-emitting diodes depending on the thickness variation of BCP using electron transport layer. The thickness of TPD and Alq3 was manufactured 40 nm, 60 nm under a base pressure of 5×106 Torr using at thermal evaporation, respectively. The TPD and Alq3 layer were evaporated to be deposition rate of 2.5\AA/s. And the BCP was evaporated to be a4 a deposition of 1.0\AA/s. As the experimental results, we found that the luminous efficiency and the external quantum efficiency of the device is superior to others when thickness of BCP is 5 nm. Also, operating voltage is lowest. Compared to the ones from the devices without BCP layer, the luminous efficiency and the external quantum efficiency were improved by a factor of four hundred ninty and five hundred, respectively. And operating voltage is reduced to about 2 V.

Cover Layer Design and Temperature Analysis in Pseudo NFR System Using SIL Head (SIL 헤드유사 근접장 시스템 개발을 위한 보호막 설계 및 열해석)

  • Kim Kyungho;Kim Sookyung;Lee Sung-Q;Park Kang-Ho;Lee Seung-Yop
    • Transactions of the Society of Information Storage Systems
    • /
    • v.1 no.1
    • /
    • pp.58-66
    • /
    • 2005
  • Pseudo-Near Field Recording (Pseudo-NFR) system is proposed to prevent contamination and oxidation of media surface occurred in conventional NFR systems. To solve these critical problems of the NFR systems, we investigate the optimal thickness of cover layer for Pseudo NFR. This paper presents the theoretical analysis for cover layer thickness based on the measured length of dust particle and numerical simulation for the temperature distribution using Finite Difference Time Domain (FDTD) method and heat conduction equation. To verify the simulation results, we conduct and compare simulation results in case of far field MO recording and near field MO recording. A measured dust particle length in general environment was mostly less than 20μm, and the optimal thickness of cover layer is 30μm in this case. Based on the designed optimal cover layer thickness, temperature distribution is simulated to have 800\~850C.

  • PDF