• Title, Summary, Keyword: Convergence Research

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Light Effects on the Bias Stability of Transparent ZnO Thin Film Transistors

  • Shin, Jae-Heon;Lee, Ji-Su;Hwang, Chi-Sun;KoPark, Sang-Hee;Cheong, Woo-Seok;Ryu, Min-Ki;Byun, Chun-Won;Lee, Jeong-Ik;Chu, Hye-Yong
    • ETRI Journal
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    • v.31 no.1
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    • pp.62-64
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    • 2009
  • We report on the bias stability characteristics of transparent ZnO thin film transistors (TFTs) under visible light illumination. The transfer curve shows virtually no change under positive gate bias stress with light illumination, while it shows dramatic negative shifts under negative gate bias stress. The major mechanism of the bias stability under visible illumination of our ZnO TFTs is thought to be the charge trapping of photo-generated holes at the gate insulator and/or insulator/channel interface.

Scalable Network Architecture for Flow-Based Traffic Control

  • Song, Jong-Tae;Lee, Soon-Seok;Kang, Kug-Chang;Park, No-Ik;Park, Heuk;Yoon, Sung-Hyun;Chun, Kyung-Gyu;Chang, Mi-Young;Joung, Jin-Oo;Kim, Young-Sun
    • ETRI Journal
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    • v.30 no.2
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    • pp.205-215
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    • 2008
  • Many control schemes have been proposed for flow-level traffic control. However, flow-level traffic control is implemented only in limited areas such as traffic monitoring and traffic control at edge nodes. No clear solution for end-to-end architecture has been proposed. Scalability and the lack of a business model are major problems for deploying end-to-end flow-level control architecture. This paper introduces an end-to-end transport architecture and a scalable control mechanism to support the various flow-level QoS requests from applications.

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Fourier Domain Optical Coherence Tomography for Retinal Imaging with 800-nm Swept Source: Real-time Resampling in k-domain

  • Lee, Sang-Won;Song, Hyun-Woo;Kim, Bong-Kyu;Jung, Moon-Youn;Kim, Seung-Hwan;Cho, Jae-Du;Kim, Chang-Seok
    • Journal of the Optical Society of Korea
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    • v.15 no.3
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    • pp.293-299
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    • 2011
  • In this study, we demonstrated Fourier-domain/swept-source optical coherence tomography (FD/SS-OCT) at a center wavelength of 800 nm for in vivo human retinal imaging. A wavelength-swept source was constructed with a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, isolators, and a fiber coupler in a ring cavity. Our swept source produced a laser output with a tuning range of 42 nm (779 to 821 nm) and an average power of 3.9 mW. The wavelength-swept speed in this configuration with bidirectionality is 2,000 axial scans per second. In addition, we suggested a modified zero-crossing method to achieve equal sample spacing in the wavenumber (k) domain and to increase the image depth range. FD/SS-OCT has a sensitivity of ~89.7 dB and an axial resolution of 10.4 ${\mu}m$ in air. When a retinal image with 2,000 A-lines/frame is obtained, an acquisition speed of 2.0 fps is achieved.

Optical and Dielectric Properties of Chalcogenide Glasses at Terahertz Frequencies

  • Kang, Seung-Beom;Kwak, Min-Hwan;Park, Bong-Je;Kim, Sung-Il;Ryu, Han-Cheol;Chung, Dong-Chul;Jeong, Se-Young;Kang, Dae-Won;Choi, Sang-Kuk;Paek, Mun-Cheol;Cha, Eun-Jong;Kang, Kwang-Yong
    • ETRI Journal
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    • v.31 no.6
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    • pp.667-674
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    • 2009
  • Terahertz time-domain spectroscopy has been used to study the optical and dielectric properties of three chalcogenide glasses: $Ge_{30}As_8Ga_2Se_{60}$, $Ge_{35}Ga_5Se_{60}$, and $Ge_{10}As_{20}S_{70}$. The absorption coefficients ${\alpha}({\nu})$, complex refractive index n(${\nu}$), and complex dielectric constants ${\varepsilon}({\nu})$ were measured in a frequency range from 0.3 THz to 1.5 THz. The measured real refractive indices were fitted using a Sellmeier equation. The results show that the Sellmeier equation fits well with the data throughout the frequency range and imply that the phonon modes of glasses vary with the glass compositions. The theory of far-infrared absorption in amorphous materials is used to analyze the results and to understand the differences in THz absorption among the sample glasses.

Nanogap Array Fabrication Using Doubly Clamped Freestanding Silicon Nanowires and Angle Evaporations

  • Yu, Han-Young;Ah, Chil-Seong;Baek, In-Bok;Kim, An-Soon;Yang, Jong-Heon;Ahn, Chang-Guen;Park, Chan-Woo;Kim, Byung-Hoon
    • ETRI Journal
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    • v.31 no.4
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    • pp.351-356
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    • 2009
  • We present a simple semiconductor process to fabricate nanogap arrays for application in molecular electronics and nano-bio electronics using a combination of freestanding silicon nanowires and angle evaporation. The gap distance is modulated using the height of the silicon dioxide, the width of the Si nanowires, and the evaporation angle. In addition, we fabricate and apply the nanogap arrays in single-electron transistors using DNA-linked Au nanoparticles for the detection of DNA hybridization.

40 Gb/s Traveling-Wave Electroabsorption Modulator-Integrated DFB Lasers Fabricated Using Selective Area Growth

  • Kwon, Yong-Hwan;Choe, Joong-Seon;Sim, Jae-Sik;Kim, Sung-Bock;Yun, Ho-Gyeong;Choi, Kwang-Seong;Choi, Byung-Seok;Nam, Eun-Soo
    • ETRI Journal
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    • v.31 no.6
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    • pp.765-769
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    • 2009
  • In this paper, we present the fabrication of 40 Gb/s traveling-wave electroabsorption modulator-integrated laser (TW-EML) modules. A selective area growth method is first employed in 40 Gb/s EML fabrication to simultaneously provide active layers for lasers and modulators. The 3 dB bandwidth of a TW-EML module is measured to be 34 GHz, which is wider than that of a lumped EML module. The 40 Gb/s non-return-to-zero eye diagram shows clear openings with an average output power of +0.5 dBm.

A Subthreshold CMOS RF Front-End Design for Low-Power Band-III T-DMB/DAB Receivers

  • Kim, Seong-Do;Choi, Jang-Hong;Lee, Joo-Hyun;Koo, Bon-Tae;Kim, Cheon-Soo;Eum, Nak-Woong;Yu, Hyun-Kyu;Jung, Hee-Bum
    • ETRI Journal
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    • v.33 no.6
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    • pp.969-972
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    • 2011
  • This letter presents a CMOS RF front-end operating in a subthreshold region for low-power Band-III mobile TV applications. The performance and feasibility of the RF front-end are verified by integrating with a low-IF RF tuner fabricated in a 0.13-${\mu}m$ CMOS technology. The RF front-end achieves the measured noise figure of 4.4 dB and a wide gain control range of 68.7 dB with a maximum gain of 54.7 dB. The power consumption of the RF front-end is 13.8 mW from a 1.2 V supply.