• Title/Summary/Keyword: Quantum-well

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Microstructure and magnetic properties of nanocomposite permanent magnetic materials

  • Cheng, Zhao-hua
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.22-22
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    • 2002
  • It is well known that nanoscale magnetic materials can exhibit significantly different magnetic properties than the corresponding bulk materials. In present work, we summarized the preparation, microstructure, Mossbauer study and magnetic properties of nanocomposites. It was found that both grain size and the amount of magnetically soft phase ${\alpha}$-Fe play a very important role in determining the magnetic properties. (omitted)

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Fabrication and Characterization of High Performance Planar Photodetectors on QW-FET Wafer (QW-FET 구조를 가진 고성능 평판형 광검출기의 제작 및 특성평가)

  • Cho, Young-Jun
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2300-2302
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    • 2005
  • Metal-Semiconductor-Metal type photodetector was fabricated with AlGaAs/InGaAs Quantum Well FET structures using simplified processing steps. The DC and RF responses were measured by 850nm wavelength injection laser. A DC responsivity in the quasisaturated regime was 0.45 A/W in CW measurements, and a bandwidth measured using a 850nm 40 ps pulsed laser was 16GHz. An electrical equivalent circuit model was extracted from measured S-parameter.

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Optical Scattering as a Probe of Local Field Effect in Micron-sized Cds Spheres

  • 김성규;Alan L. Huston;Anthony J. Campillo
    • Bulletin of the Korean Chemical Society
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    • v.16 no.2
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    • pp.96-101
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    • 1995
  • The optical properties of individual 3-to 14-micron diameter CdS crystalline spheres embedded in poly(methyl methacrylate) were studied using elastic scattering. The presence of well defined sharp peaks in the 550 to 600 nm elastic scattering spectra confirmed that each microcrystal acts as an optical cavity with cavity quality factors exceeding 104. Such natural resonator microcrystals should lead to greatly enhanced local field effects near the surface of CdS, quantum electrodynamic modification of optical transition rates of nearby species and altered photochemistry. Absorptive heating following high intensity laser irradiation was found to induce a transient washout of the high Q modes.

Spectral Behaviors of Unidirectional Lasing from Various Semiconductor Square Ring Microcavities

  • Moon, Hee-Jong;Hyun, Kyung-Sook;Lim, Changhwan
    • Journal of the Korean Physical Society
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    • v.73 no.10
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    • pp.1506-1511
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    • 2018
  • Spectral behaviors of lasing from semiconductor square ring microcavities with structures for unidirectional laser oscillation were investigated. When a tapered structure was introduced, the lasing envelope shifted to a shorter wavelength region. Statistical estimate of the additional loss caused by the tapered structure was carried out by analyzing spectral data from many sets of cavities with various sizes. When a saw-edged structure was introduced, the unidirectional lasing functioned well but no apparent spectral shift was observed due to negligible additional loss.