• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집
• /
• pp.43-48
• /
• 2004

Undoped and $Co^{2+}$-doped $CaGa_2S_4$, $CaGa_2Se_4$, $CaIn_2S_4$. and $CaIn_2Se_4$ single crystals were grown by using the chemical transport reaction method The temperature dependence of the optical energy gap was well fitted by the Varshni equation. In the Co2+ - doped $CaGa_2S_4$, $CaGa_2Se_4$, $CaIn_2S_4$, and $CaIn_2Se_4$ single crystals, two groups of impurity optical absorption peaks due to Co2+ sited in a Td symmetry were observed in the wavelength regions of 600 900 nm and 1350 1950 nm at 11 K.耀

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
• /
• pp.85-86
• /
• 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 temperature dependence of the energy band gap of the $AgGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=19501 eV-(879{\times}10^{-4} eV/K)T^2/(T+250 K)$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.96-97
• /
• 2008

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 def Pauw method are $9.24\times10^{16}cm^{-3}$ and 295 $cm^2/V{\cdot}s$ at 293 K, respectively.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 D
• /
• pp.1264-1267
• /
• 1998

$Cu(In_xGa_{1-x})Se_2$ thin films were prepared and characterized with various Ga contents. As the Ga content increased, the grain size of CIGS film became smaller. The 2 $\theta$ values in XRD patterns were shifted to larger values and the overlapped peaks were splitted. The energy bandgap increased from 1.04 to 1.67 eV and the resistivity decreased. The solar cell fabricated with ZnO/CdS/$Cu(In_{0.7}Ga_{0.3})Se_2/Mo$ structure yielded an efficeincy of 14.48% with an acitive area of 0.18 $cm^2$. The efficiency decreased with further increase of Ga content.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.171-174
• /
• 2004

The stochiometric $AgGaSe_2$ polycrystalline mixture of evaporating materials for the $AgGaSe_2$ single crystal thin film was prepared from horizontal furnace. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal and semi-insulating GaAs(100) wafer were used as source material and substrate for the Hot Wall Epitaxy (HWE) system, respectively. The source and substrate temperature were fixed at $630^{\circ}C$ and $420^{\circ}C$, respectively. The thickness of grown single crystal thin films is $2.1{\mu}m$. The single crystal thin films were investigated by photoluminescence and double crystal X-ray diffraction(DCXD) measurement. The carrier density and mobility of $AgGaSe_2$ single crystal thin films measured from Hall effect by van der Pauw method are $4.89{\times}10^{17}\;cm^{-3},\;129cm^2/V{\cdot}s$ at 293K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the $AgGaSe_2$ single crystal thin film, we have found that the values of spin orbit splitting ${\Delta}S_o$ and the crystal field splitting ${\Delta}C_r$ were 0.1762 eV and 0.2494 eV at 10 K, respectively. From the photoluminescence measurement of $AgGaSe_2$ single crystal thin film, we observed free excition $(E_X)$ observable only in high quality crystal and neutral bound exciton $(D^o,X)$ having very strong peak intensity And, the full width at half maximum and binding energy of neutral donor bound excition were 8 meV and 14.1 meV, respectively. By Haynes rule, an activation energy of impurity was 141 meV.

• 센서학회지
• /
• 제15권6호
• /
• pp.397-405
• /
• 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.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.97-98
• /
• 2007

A stoichiometric. mixture of evaporating materials for $CuGaSe_2$ single crystal thin films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuGaSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.615\;{\AA}$ and $11.025\;{\AA}$, respectively. To obtain the single crystal thin films, $CuGaSe_2$ 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 $610^{\circ}C$ and $450^{\circ}C$, 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 $CuGaSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $4.87{\times}10^{17}\;cm^{-3}$ and $129\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;1.7998\;eV\;-\;(8.7489\;{\times}\;10^{-4}\;eV/K)T^2/(T\;+\;335\;K)$.

• Bulletin of the Korean Chemical Society
• /
• 제16권7호
• /
• pp.588-591
• /
• 1995

Single crystals of (ZnSe)1-x(CuMSe2)x (M=Al, Ga, or In) were grown by chemical vapor transport technique. Powdered polycrystalline samples of (ZnSe)1-x(CuMSe2)x (M=Al, Ga, or In) were also prepared by the direct combination of the elements. The chemical composition of these single crystals was determined by comparing their lattice parameters with those of the standard polycrystalline samples. The IR transmission range of single crystals of (ZnSe)1-x(CuMSe2)x (M=Al, Ga, or In) is slightly narrower than that observed for pure ZnSe. However, these materials still show good transmission in the long-wavelength IR range. The addition of small amounts of CuMSe2 (M=Al, Ga, or In) considerably increases the hardness of ZnSe.

• 한국진공학회지
• /
• 제21권6호
• /
• pp.322-327
• /
• 2012

Molecular beam epitaxy 방법으로 성장된 ZnSe/GaAs 이종접합 구조에서 ZnSe의 electroreflectance (ER) 특성을 조사하였다. ER 측정은 변조 전압, 인가 전압 및 온도의 변화에 따라 수행하였다. 상온의 ZnSe ER 스펙트럼에서 압축 변형에 의하여 분리된 가전자대의 무거운 정공(HH: 2.609 eV) 및 가벼운 정공(LH: 2.628 eV)과 전도대 사이의 전이를 관측하였다. 인가전압이 증가함에 따라 HH 전이 신호의 크기는 점차 감소하였으나, LH 전이 신호의 크기 변화는 미미하였다. 온도에 따른 ER 스펙트럼의 변화를 통하여 변형과 열팽창 계수와의 관계를 연구하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.361-361
• /
• 2011

Cu(InGa)(SeS2) (CIGS) thin film solar cells have recently reached an efficiency of 20%. Recent studies suggest a double graded band gap structure of the CIGS absorber layer to be a key issue in the production of high efficiency thin film solar cell using by sputtering process method. In this study, Cu(InGa)(SeS2) absorbers were manufactured by selenization and surfulization, we have deposited CIG precusor by sputtering and Se layer by evaporation before selenization. The objective of this study is to find out surfulization effects to improve Voc and to compare with non-surfulization Cu(InGa)Se2 absorbers. Even if we didn't analysis Ga depth profile of Cu(InGa)(SeS2) absorbers, we confirmed increasing of Eg and Voc through surlization process. In non-surfulization Cu(InGa)Se2 absorbers, Eg and Voc are 0.96eV and 0.48V. Whereas Eg and Voc of Cu(InGa)(SeS2) absorbers are 1.16eV and 0.57V. And the efficiency of 9.58% was achieved on 0.57cm2 sized SLG substrate. In this study, we will be discussed to improve Eg and Voc through surfulization and the other method without H2S. gas.