• 제목/요약/키워드: Crystal field splitting

검색결과 111건 처리시간 0.028초

Theoretical Calculation of Zero Field Splitting of $Mn^{2+}$ Ion in $LiTaO_3$Crystal

  • Yeom, T.H;Lee, S.H
    • Journal of Magnetics
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    • 제6권3호
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    • pp.77-79
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    • 2001
  • The semi-empirical superposition model has been applied to calculate the zero field splitting parameters of $Mn^{2+}$ion in $LiTaO_3$ single crystal, assuming that $Mn^{2+}$ion occupies one of two possible sites: $Li^{l+} \;or\; Ta^{5+}$ site, respectively. The 2nd-order axial zero field splitting parameters are $958\times10^{-4}cm^{-1}\; at\; Li^{1+}$ site and $193\times 10^{-4}cm^{-1} \;at\; Ta^{5+}$ site for $Mn^{2+}$ions. The 4th-order zero field splitting parameters at $Li^{l+} \;and\; Ta^{5+}$ sites are also determined. These calculated zero field splitting parameters are very important to determine the substitutional sites of doped impurity ions in $LiTaO_3$ crystal.

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Integral Hellmann-Feynman Approach에 의한 KNiF$_3$의 Cubic Crystal Field Splitting 10 Dq의 계산 (Calculation of the Cubic Crystal Field Splitting 10 Dq in KNiF$_3$. An Integral Hellmann-Feynman Approach)

  • 김호징;김희준
    • 대한화학회지
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    • 제17권6호
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    • pp.395-405
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    • 1973
  • Integral Hellmann-Feynman formula를 사용하여 $KNiF_3$의 cubic crystal splitting 10Dq를 first principle로부터 계산하였다. Covalency parameter들과 필요한 적분치들은 Sugano와 Shulman의 계산치를 사용하였다. 계산치 7100$cm^{-1}$는 실험치 7250$cm^{-1}$와 대단히 잘 일치하였다. 고차섭동에너지 보정치는 10 Dq 자체와 같은 order of magnitude를 가지며 따라서 first principle로부터 10 Dq를 계산하는데 있어서 반드시 고려되어야 할 몫이라는 것을 발견하였다. 또한 point charge potential이 crystal field potential의 압도적인 부분을 차지하는 것을 발견하였다.

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Hot Walll Epitaxy (HWE)법에 의한 $CuInSe_2$ 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구 (Growth and Photocurrent Study on the Splitting of the Valence Band for $CuInSe_2$ Single Crystal Thin Film by Hot Wall Epitaxy)

  • 윤석진;홍광준
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.234-238
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    • 2004
  • A stoichiometric mixture of evaporating materials for $CuInSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuInSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $620^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuInSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.62{\times}10^{l6}\;cm^{-3}$ and $296\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuInSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;1.1851\;eV\;-\;(8.99{\times}10^{-4}\;eV/K)T^2/(T+153K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CuInSe_2$ have been estimated to be 0.0087 eV and 0.2329 eV at 10K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}_{so}$ definitely exists in the $\Gamma_6$ states of the valence band of the $CuInSe_2$. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.

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Hot Wall Epitaxy(HWE)범에 의한 $CuInSe_2$ 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구 (Growth and photocurrent study on the splitting of the valence band for $CuInSe_2$ single crystal thin film by hot wall epitaxy)

  • 홍명석;홍광준
    • 한국결정성장학회지
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    • 제14권6호
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    • pp.244-252
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    • 2004
  • $CuISe_2$ 단결정 박막은 수평 전기로에서 합성한 $CuInSe_2$ 다결정을 증발원으로하여, hot wall epitaxy(HWE) 방법으로 증발원과 기판(반절연성-GaAs(100))의 온도를 각각 $620^{\circ}C$, $410^{\circ}C$로 고정하여 단결정 박막을 성장하였다. 이때 단결정 박막의 결정성은 광발광 스펙트럼과 이중결정 선 요동곡선(DCRC) 으로 부터 구하였다. Hall 효과는 van der Pauw 방법에 의해 측정되었으며, 293K에서 운반자 농도와 이동도는 각각 $9.62\times10^{16}/\textrm{cm}^3$, 296 $\textrm{cm}^2$/Vㆍs 였다. $CuAlSe_2$/Si(Semi-Insulated) GaAs(100) 단결정 박막의 광흡수와 광전류 spectra를 293k에서 10K까지 측정하였다. 광흡수 스펙트럼으로부터 band gap $E_g$(T)는 Varshni 공식에 따라 계산한 결과 1.1851 eV-($8.99\times10^{-4} eV/K)T^2$/(T+153k)였다. 광전류 스펙트럼으로 부터 Hamilton matrix(Hopfield quasicubic mode)법으로 계산한 결과 crystal field splitting Δcr값이 0.0087eV이며 spin-orbit Δso값은 0.2329 eV임을 확인하였다. 10K일 때 광전류 봉우리들은 n = 1일때 $A_1-, B_1$-와 $C_1$-exciton봉우리임을 알았다.

광전류 측정으로부터 얻어진 $CdGa_2Se_4$ 에피레이어의 결정장 갈라짐에 대한 에너지 (Crystal field splitting energy for $CdGa_2Se_4$ epilayers obtained by photocurrent measurement)

  • 홍광준
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.144-145
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    • 2009
  • Single crystal $CdGa_2Se_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the poly crystal source of $CdGa_2Se_4$ at $630\;^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $CdGa_2Se_4$ thin films measured with Hall effect by van der Pauw method are $8.27\;\times\;10^{17}\;cm^{-3}$, $345\;cm^2/V{\cdot}s$ at 293 K, respectively. The photocurrent and the absorption spectra of $CdGa_2Se_4$/SI(Semi-Insulated) GaAs(100) are measured ranging from 293 K to 10K. The temperature dependence of the energy band gap of the $CdGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T) = 2.6400 eV - ($7.721\;{\times}\;10^{-4}\;eV/K)T^2$/(T + 399 K). Using the photocurrent spectra and the Hopfield quasi cubic model, the crystal field energy(${\Delta}cr$) and the spin-orbit splitting energy(${\Delta}so$) for the valence band of the $CdGa_2Se_4$ have been estimated to be 106.5 meV and 418.9 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_1$-, $B_1$-, and $C_{11}$-exciton peaks.

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Hot Wall Epitaxy(HWE)법에 의한 AgGaSe2 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구 (Growth and study on photocurrent of valence band splitting for AgGaSe2 single crystal thin film by hot wall epitaxy)

  • 이관교;홍광준
    • 센서학회지
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    • 제15권6호
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    • pp.397-405
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    • 2006
  • Single crystal $AgGaSe_{2}$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $AgGaSe_{2}$ source at $630^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $AgGaSe_{2}$ thin films measured with Hall effect by van der Pauw method are $4.05{\times}10^{16}/cm^{3}$, $139cm^{2}/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $AgGaSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$=1.9501 eV-($8.79{\times}10^{-4}{\;}eV/K)T^{2}$/(T+250 K). The crystal field and the spin-orbit splitting energies for the valence band of the $AgGaSe_{2}$ have been estimated to be 0.3132 eV and 0.3725 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}So$ definitely exists in the ${\Gamma}_{5}$ states of the valence band of the $AgGaSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-$, and $C_{1}-$exciton peaks for n=1.

$CdIn_2Te_4$ 결정의 띠간격 에너지의 온도 의존성과 가전자대 갈라짐에 대한 연구 (Band gap energy and photocurrent splitting for CdIn2Te4 crystal by photocurrent spectroscopy)

  • 홍광준;김도선
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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    • pp.121-122
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    • 2006
  • Single crystal of $CdIn_2Te_4$ were grown by the Bridgman method without using seed crystals. From photocurrent measurements, its was found that three peaks, A, B, and C, correspond to the instrinsic transition from the valence band states of ${\Gamma}_7$(A), ${\Gamma}_6$(B), and ${\Gamma}_7$(C) to the conducton band states of ${\Gamma}_6$, respectively. Crystal field splitting and spin orbit splitting were found to be at 0.2360 eV and 0.1119 eV, respectively, from found to be photocurrent spectroscopy.

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$CuAlSe_2$ 단결정 박막의 성장과 광전류 특성 (Growth and Photocurrent Properties for $CuAlSe_2$ Single Crystal Thin film)

  • 홍광준;백승남
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.226-229
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    • 2004
  • A stoichiometric mixture of evaporating materials for $CuAlSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;2.8382\;eV\;-\;(8.68{\times}10^{-4}\;eV/K)T^2/(T+155K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_2$ have been estimated to be 0.2026 eV and 0.2165 eV at 10K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $CuAlSe_2$. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.

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