• 센서학회지
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• 제13권2호
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• pp.157-167
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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 $295cm^{2}/V{\codt}s$ 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 - ($8.68{\circ}10^{-4}$ eV/K)$T^{2}$/(T + 155 K). 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 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 $CuAlSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1-}$, $B_{1-}$, and $C_{1-}$ exciton peaks for n = 1.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.111-112
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• 2005

To obtain the single crystal thin films, $CuInSe_2$, mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wail 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 mobilily of $CuInSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.62\times10^{16}$ $cm^{-3}$ and $296cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the CulnSe$_2$ obtained from the absorption spectra was well described by the Varshni's relation E$_g$(T) = 1.1851 eV - ($8.99\times10^{-4}$ ev/K)T$_2$/(T + 153K). After the as-grown $CuInSe_2$ single crystal thin films was annealed in Cu-, Se-, and In-atmospheres the origin of point defects of $CuInSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The nat ive defects of V$_{Cu}$, $V_{Se}$, Cu$_{int}$, and $Se_{int}$ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuInSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that In in $CuInSe_2$/GaAs did not form the native defects because In in $CuInSe_2$ single crystal thin films existed in the form of stable bonds.

• 센서학회지
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• 제23권2호
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• pp.134-141
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• 2014

A stoichiometric mixture of evaporating materials for $BaIn_2Se_4$ epilayers was prepared from horizontal electric furnace. To obtain the single crystal thin films, $BaIn_2Se_4$ 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 $400^{\circ}C$, respectively. The crystalline structure of the epilayers was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $BaIn_2Se_4$ epilayers measured from Hall effect by van der Pauw method are $8.94{\times}10^{17}cm^{-3}$ and 343 $cm^2/vs$ at 293 K, respectively. The temperature dependence of the energy band gap of the $BaIn_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)$=2.6261 eV-$(4.9825{\times}10^{-3}eV/K)T^2/(T+558 K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $BaIn_2Se_4$ have been estimated to be 116 meV and 175.9 meV, 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 $BaIn_2Se_4/GaAs$ epilayer. The three photocurrent peaks observed at 10 K are ascribed to the $A_1-$, $B_1$-exciton for n = 1 and $C_{21}$-exciton peaks for n=21.

• 태양에너지
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• 제13권1호
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• pp.49-58
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• 1993

승화방법에 의해 $CdS_{0.46}Se_{0.54}$ 단결정을 성장하여 결정구조를 조사하고, Van der Pauw 방법으로 Hall effect를 측정하여 carrier density의 온도 의존성과 mobility의 온도 의존성을 조사하였다. 성장된 $CdS_{0.46}Se_{0.54}$ 단결정을 치환반응하여 $n-CdS_{0.46}Se_{0.54}/p-Cu_{2-X}S_{0.46}Se_{0.54}$ 이종접합 태양전지를 제작하였다. Spectral response, 전류-전압특성 및 전력변환 효율을 조사하여 그 결과로부터 개방전압은 0.48V, 단락 전류 밀도는 $21mA/cm^2$, fill factor와 전력변환효율은 각각 0.75와 9.5%를 얻었다.

• 센서학회지
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• 제24권6호
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• pp.404-411
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• 2015

A stoichiometric mixture of evaporating materials for $BaAl_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $BaAl_2Se_4$ 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 $610^{\circ}C$ 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 $BaAl_2Se_4$ single crystal thin films measured from Hall effect by van der Pauw method are $8.29{\times}10^{-16}cm^{-3}$ and $278cm^2/vs$ at 293 K, respectively. The temperature dependence of the energy band gap of the $BaAl_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=3.4205eV-(4.3112{\times}10^{-4}eV/K)T^2/(T+232 K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $BaAl_2Se_4$ have been estimated to be 249.4 meV and 263.4 meV, 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 $BaAl_2Se_4/GaAs$ epilayer. The three photocurrent peaks observed at 10 K are ascribed to the $A_1$-, $B_1$-exciton for n =1 and $C_{31}$-exciton peaks for n=31.

• 센서학회지
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• 제10권1호
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• pp.62-70
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• 2001

CBD방법으로 성장하여 $450^{\circ}C$로 열처리한 ZnSe 박막은 회전 무늬로부터 외삽법으로 구한 격자상수 $a_0$가 $5.6678\;{\AA}$인 zinc blend임을 알았다. Van der Pauw 방법으로 측정한 Hall 데이터에 의한 이동도는 10 K에서 150 K 까지는 불순물 산란 (impurity scatterimg)에 의하여, 150 K에서 293 K까지는 격자산란 (lattice scattering)에 의하여 감소하는 경향을 나타냈다. 또한 운반자 농도의 ln n대 1/T에서 구한 활성화 에너지($E_a$)는 0.27 eV였다. 투과 곡선의 투과단으로 본 띠 간격은 293 k에서 $2,700{\underline{5}}\;eV$이었던 것이 10K에서는 $2.873{\underline{9}}\;eV$로 변하였다. 광전류 봉우리 위치를 투과단과 비교할 때 293 K에서 30 K까지 관측된 한 개의 봉우리는 가전자대 ${\Gamma}_8$에서 전도대 ${\Gamma}_6$로 전이에 의한 광전류 봉우리이고, 10K에서 관측된 단파장대 417.3 nm($2.971{\underline{4}}\;eV$)의 봉우리는 가전자대 ${\Gamma}_7$에서 전도대 ${\Gamma}_6$로, 431.5 nm($2.873{\underline{3}}\;eV$)의 봉우리는 가전자대 ${\Gamma}_8$에서 전도대 ${\Gamma}_6$로 전이에 의한 광전류 봉우리가 관측된 것으로 판단된다. 광전류 봉우리의 10K에서 단파장대의 가전자대 갈라짐(splitting)에 의해서 측정된 ${\Delta}so$(spin orbit coupling)는 $0.098{\underline{1}}\;eV$ 였다. 10 K에서 광발광 봉우리의 440.7 nm($2.812{\underline{7}}\;eV$)는 자유 엑시톤(free exciton : $E_x$), 443.5 nm ($2.795{\underline{5}}\;eV$)는 주개-얽매인 엑시톤(donor-bound exciton) 인 $I_2(D^0,\;X)$와 445.7 nm ($2.781{\underline{8}}\;eV$)는 반개-얽매인 엑시톤(acceptor-bound exciton) 인 $I_1(A^0,X)$이고, 460.5 nm ($2.692{\underline{3}}\;eV$)는 주개-받개쌍(donor-acceptor pair:DAP) 발광, 580 nm ($2.137{\underline{6}}\;eV$)는 self activated(A)에 기인하는 광발광 봉우리로 분석된다.