• Title/Summary/Keyword: Cu dopant

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First-principles Study on Magnetism of Cu in GaN

  • Kang, Byung-Sub;Heo, Chul-Min;Lyu, Kwang-Kwyun;Yu, Seong-Cho
    • Journal of Magnetics
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    • v.14 no.3
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    • pp.114-116
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    • 2009
  • The electronic properties of Cu or Pd-doped GaN at several concentrations are examined using the full-potential linear muffin-tin orbital method. For ($Cu_{0.055}Ga_{0.945}$)N, the model reveals a magnetic moment of $1.47{\mu}B$ per supercell. The range of concentrations that are spin-polarized should be restricted within narrow limits. A paramagnetic to ferromagnetic phase transition is found to occur at a Cu concentration of 5.55%.

Magnetic Properties of Cu-doped AlN Semiconductor (AlN 반도체와 Cu의 도핑 농도에 대한 자성)

  • Kang, Byung-Sub;Lee, Haeng-Ki
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.3
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    • pp.1-4
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    • 2010
  • First-principles calculations based on spin density functional theory are performed to study the spin-resolved electronic properties of AlN doped with a Cu concentration of 6.25%-18.75%. The ferromagnetic state is more energetically favorable state than the antiferromagnetic state or the nonmagnetic state. For $Al_{0.9375}Cu_{0.0625}N$, a global magnetic moment of 1.26 mB per supercell, with a localized magnetic moment of 0.75 $m_B$ per Cu atom is found. The magnetic moment is reduced due to an increase in the number of Cu atoms occupying adjacent cation lattice position. For $Al_{0.8125}Cu_{0.1875}N$, the magnetism of the supercell disappears by the interaction of the neighboring Cu atoms. The nonmagnetic to ferromagnetic phase transition is found to occur at this Cu concentration. The range of concentrations that are spin-polarized should be restricted within very narrow.

Structural and Electrical Properties of [(Co1-xCux)0.2(Ni0.3Mn0.7)0.8]3O4 Spinel Thin Films for Infrared Sensor Application (적외선 센서용 [(Co1-xCux)0.2(Ni0.3Mn0.7)0.8]3O4 스피넬 박막의 구조 및 전기적 특성)

  • Lee, Kui Woong;Jeon, Chang Jun;Jeong, Young Hun;Yun, Ji Sun;Cho, Jeong Ho;Paik, Jong Hoo;Yoon, Jong-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.12
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    • pp.825-830
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    • 2014
  • $[(Co_{1-x}Cu_x)_{0.2}(Ni_{0.3}Mn_{0.7})_{0.8}]_3O_4$ ($0{\leq}x{\leq}1$) thin films prepared by metal organic decomposition process were fabricated on SiN/Si substrate for infrared sensor application. Their structural and electrical properties were investigated with variation of Cu dopant. The $[(Co_{1-x}Cu_x)_{0.2}(Ni_{0.3}Mn_{0.7})_{0.8}]_3O_4$ (CCNMO) film annealed at $500^{\circ}C$ exhibited a dense microstructure and a homogeneous crystal structure with a cubic spinel phase. Their crystallinity was further enhanced with increasing doped Cu amount. The 120 nm-thick CCNMO (x=0.6) thin film had a low resistivity of $53{\Omega}{\cdot}cm$ at room temperature while the Co-free film (x=1) showed a significantly decreased resistivity of $5.9{\Omega}{\cdot}cm$. Furthermore, the negative temperature coefficient of resistance (NTCR) characteristics were lower than $-2%/^{\circ}C$ for all the specimens with $x{\geq}0.6$. These results imply that the CCNMO ($x{\geq}0.6$) thin films are a good candidate material for infrared sensor application.

Synthesis of ZnS : Cu nano-crystals and structural and optical properties (ZnS : Cu nano 업자의 합성 및 구조적.광학적 특성)

  • 이종원;이상욱;조성룡;김선태;박인용;최용대
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.12 no.3
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    • pp.138-143
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    • 2002
  • In this study, ZnS: Cu nano-crystals are synthesized by solution synthesis technique (SST). The structural properties such as crystal structure and particle morphology, and the optical properties such as light absorption/transmittance, energy bandgap, and photoluminescence (PL) excitation/emission are investigated. In an attempt to realize the Cu-doping easiness, the synthesis temperature (~$80^{\circ}C$) is applied to the synthesis bath, and the thiourea is used as sulfur precursor, unlike other general chemical synthesis route. Both undoped ZnS and ZnS : Cu nano-crystals have the cubic crystal structure and have the spherical particle shape. The position of light absorption edge is ~305 nm, indicating the occurrence of quantum size effect. The PL emission intensity and line-width are maximum and minimum, respectively, for Cu-doping concentration 0.03M. In particular, the dependence of PL intensity and line-width on the Cu-doping concentration for ZnS : Cu nano-crystals synthesized by SST is reported for the first time in this study. Experimental results of the absorption edge and the PL excitation show that the main emission peak of ZnS : Cu nano-crystals (~510 nm) in this study is due to the radiative recombination center in the energy bandgap induced by Cu dopant.