• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.167-170
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• 2001

The stochiometric mix of evaporating materials for the $CdGa_{2}Se_{4}$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CdGa_{2}Se_{4}$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CdGa_{2}Se_{4}$ single crystal thin films measured from Hall effect by van der Pauw method are $8.27{\times}10^{17}cm^{-3},345cm^{2}/V{\cdot}s$ at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $CuInSe_{2}$ single crystal thin film, we have found that the values of spin orbit splitting $\Delta$ So and the crystal field splitting $\Delta$Cr were 106.5 meV and 418.9 meV at 10 K, respectively. From the photoluminescence measurement on $CdGa_{2}Se_{4}$ single crystal thin film, we observed free excition (Ex) existing only high Quality crystal and neutral bound exiciton $(D^{0},X)$ having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy of neutral donor bound excition were 8 meV and 13.7 meV, respectivity. By Haynes rule, an activation energy of impurity was 137 meV.

• 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 2001년도 추계학술대회 논문집
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• pp.167-170
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• 2001

The stochiometric mix of evaporating materials for the CdGa$_2$Se$_4$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CdGa$_2$Se$_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 630$^{\circ}C$ and 420$^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of CdGa$_2$Se$_4$ single crystal thin films measured from Hall erect by van der Pauw method are 8.27x10$\^$17/ cm$\^$-3/, 345 $\textrm{cm}^2$/V$.$s at 293 K, respectively. From the Photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuInSe$_2$ single crystal thin film, we have found that the values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 106.5 meV and 418.9 meV at 10 K, respectively. From the photoluminescence measurement on CdGa$_2$Se$_4$ single crystal thin film, we observed free excition (E$\_$X/) existing only high quality crystal and neutral bound exiciton (D$\^$0/,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy of neutral donor bound excision were 8 meV and 13.7 meV, respectivity. By Haynes rule, an activation energy of impurity was 137 meV,

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.85.2-85.2
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• 2010

$Cu_2ZnSnSe_4$ (CZTSe) is one of candidate to alternate $Cu(In,Ga)Se_2$ as solar absorber material for solar cell. The expensive elements of In and Ga are replaced by Zn and Sn, respectively to lower the material cost. In this study we fabricated CZTSe thin film by selenization of single precursor layer consisted metallic constituent. Precursor compositions ratio were selected to have Cu-poor and Zn-rich content and prepared by RF magnetron sputtering. Thermal processing was applied to introduce selenium into as-deposited films at temperatures ranging from 350 to 500 for time up to 120 minutes. Single precursor films showed amorphous structure and consist of individual elements of Cu, Zn, and Sn. It was confirmed by XRD analysis that synthesis of CZTSe compound is occurred from lower temperature process, although concurrently additional phases such as binary cooper selenides are also existed. The quality of CZTSe crystal was improved as temperature increased. We also investigated the optical and electrical properties of as-selenized CZTSe as well.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.414-415
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• 2005

A solar cell is an element to transform the solar light energy into the electric energy in a moment. The single crystal element of high quality on which many studies were conducted in the past has a high efficiency of energy transformation, but its price competitiveness is so poor that it has failed to be popularized However, recently, in terms of an environment-friendly alternative energy, studies on applicability of the polycrystal solar cell have been actively under way. Among subject substances for such solar cell, $CuInSe_2$ has several good physical properties so that the greatest attention is paid to it as an optical absorption layer material for a low-cost solar cell of high efficiency. In order to manufacture the $CuInSe_2$ compound thin film, the unit element was deposited by using the sputtering method and the evaporation method and the heat treatment process was used in an electric furnace. Thereby, we intended to get a single-phase $CuInSe_2$ compound thin film.

• 센서학회지
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• 제10권6호
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• pp.328-337
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• 2001

수평 전기로에서 $CdGa_2Se_4$ 다결정을 합성하여 HWE 방법으로 $CdGa_2Se_4$ 단결정 박막을 반절연성 GaAs(100) 위에 성장하였다. $CdGa_2Se_4$ 단결정 박막은 증발원과 기판의 온도를 각각 $630^{\circ}C$, $420^{\circ}C$로 성장하였다. 10K에서 측정한 광발광 exciton 스펙트럼과 이중결정 X-선 요동곡선(DCRC)의 반치폭(FWHM)을 분석하여 단결정 박막의 최적 성장 조건을 얻었다. Hall 효과는 van der Pauw 방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 $8.27{\times}10^{17}/cm^3$, $345\;cm^2/V{\cdot}s$였다. 광전류 봉우리의 10K에서 단파장대의 가전자대 갈라짐(splitting)에 의해서 측정된 ${\Delta}Cr$ (crystal field splitting)은 106.5 meV, ${\Delta}So$ (spin orbit splitting)는 418.9 meV였다. 10K의 광발광 측정으로부터 고품질의 결정에서 볼 수 있는 free exciton 과 매우 강한 세기의 중성 주개 bound exciton등의 피크가 관찰되었다. 이때 중성 주개 bound exciton의 반치폭과 결합 에너지는 각각 8 meV와 13.7 meV였다. 또한 Haynes rule에 의해 구한 불순물의 활성화 에너지는 137 meV 였다.

• 한국전기전자재료학회논문지
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• 제24권2호
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• pp.162-165
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• 2011

In this paper, $CuInSe_2$ thin film was prepared by use of the co-evaporation method with the variation of the substrate temperature in the range of $100^{\circ}C$ to $400^{\circ}C$. The film was annealed at $300^{\circ}C$ for an hour in a vacuum chamber at $3{\times}10-4$ Pa. After annealing, the thin film prepared at the substrate temperatures of $100^{\circ}C$ and $200^{\circ}C$ was observed. The XRD (x-ray diffraction) pattern of sample prepared at $100^{\circ}C$ showed the single phase formation of $CuInSe_2$. However, at $200^{\circ}C$, there was no apparent difference in the XRD pattern except a variation in the intensity of the peak. As the annealing treatment of substrate improved the crystal structure of the film, it affected to the increase of an electron mobility, resulted in an increase in conductivity and a decrease in resistance. As a results, when the substrate temperature was at $200^{\circ}C$ and $300^{\circ}C$, the sheet resistance was 1.534 $\Omega/\Box$ and 1.554 $\Omega/\Box$, respectively, and the resistivity was $1.76{\times}10-6\;{\Omega}{\cdot}cm$ and $1.7210-6\;{\Omega}{\cdot}cm$, respectively. From the absorption spectrum measurements, there was no variation between the before and after annealing conductions. And it means that the annealing step does not affect the thickness of the thin film.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.398.1-398.1
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• 2014

The $Cu_2ZnSnSe_4$ (CZTSe) thin films solar cell is one of the next generation candidates for photovoltaic materials as the absorber of thin film solar cells because it has optimal bandgap (Eg=1.0eV) and high absorption coefficient of $10^4cm^{-1}$ in the visible length region. More importantly, CZTSe consists of abundant and non-toxic elements, so researches on CZTSe thin film solar cells have been increasing significantly in recent years. CZTSe thin film has very similar structure and properties with the CIGS thin film by substituting In with Zn and Ga with Sn. In this study, As-deposited CZTSe thin films have been deposited onto soda lime glass (SLG) substrates at different deposition condition using Pulsed Laser Deposition (PLD) technique without post-annealing process. The effects of deposition conditions (deposition time, deposition temperature) onto the structural, compositional and optical properties of CZTSe thin films have been investigated, without experiencing selenization process. The XRD pattern shows that quaternary CZTSe films with a stannite single phase. The existence of (112), (204), (312), (008), (316) peaks indicates all films grew and crystallized as a stannite-type structure, which is in a good agreement with the diffraction pattern of CZTSe single crystal. All the films were observed to be polycrystalline in nature with a high (112) predominant orientation at $2{\theta}{\sim}26.8^{\circ}$. The carrier concentration, mobility, resistivity and optical band gap of CZTSe thin films depending on the deposition conditions. Average energy band gap of the CZTSe thin films is about 1.3 eV.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.158-158
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• 2011

$Cu(In_xGa_{1-x})Se_2$ (CIGS) thin film solar cell is one of the most promising solar cells in photovoltaic devices. CIGS has a direct band gap which varied from 1.0 to 1.26 eV, depending on the Ga to In ratio. Also, CIGS has been studying for an absorber in thin film solar cells due to their highest absorption coefficient which is $1{\times}10^5cm^{-1}$ and good stability for deposition process at high temperature of $450{\sim}590^{\circ}C$. Currently, the highest efficiency of CIGS thin film solar cell is approximately 20.3%, which is closely approaching to the efficiency of poly-silicon solar cell. The deposition technique is one of the most important points in preparing CIGS thin film solar cells. Among the various deposition techniques, the sputtering is known to be very effective and feasible process for mass production. In this study, CIGS thin films have been prepared by rf magnetron sputtering method using a single target. The optical and structural properties of CIGS films are generally dependent on deposition parameters. Therefore, we will explore the influence of deposition power on the properties of CIGS films and the films will be deposited by rf magnetron sputtering using CIGS single target on Mo coated soda lime glass at $500^{\circ}C$. The thickness of CIGS films will be measured by Tencor-P1 profiler. The optical properties will be measured by UV-visible spectroscopy. The crystal structure will be analyzed using X-ray diffraction (XRD). Finally the optimal deposition conditions for CIGS thin films will be developed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.159-159
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• 2011

Among the semiconductor ternary compounds in the I-III-$VI_2$ series, $CulnS_2$ ($CulnSe_2$) are one of the promising materials for photovoltaic applications because of the suitability of their electrical and optical properties. The $CuInS_2$ thin film is one of I-III-$VI_2$ type semiconductors, which crystallizes in the chalcopyrite structure. Its direct band gap of 1.5 eV, high absorption coefficient and environmental viewpoint that $CuInS_2$ does not contain any toxic constituents make it suitable for terrestrial photovoltaic applications. A variety of techniques have been applied to deposit $CuInS_2$ thin films, such as single/double source evaporation, coevaporation, rf sputtering, chemical vapor deposition and chemical spray pyrolysis. This is the first report that $CuInS_2$ thin films have been prepared by Aerosol Jet Deposition (AJD) technique which is a novel and attractive method because thin films with high deposition rate can be grown at very low cost. In this study, $CuInS_2$ thin films have been prepared by Aerosol Jet Deposition (AJD) method which employs a nozzle expansion. The mixed fluid is expanded through the nozzle into the chamber evacuated in a lower pressure to deposit $CuInS_2$ films on Mo coated glass substrate. In this AJD system, the characteristics of $CuInS_2$ films are dependent on various deposition parameters, such as compositional ratio of precursor solution, flow rate of carrier gas, stagnation pressure, substrate temperature, nozzle shape, nozzle size and chamber pressure, etc. In this report, $CuInS_2$ thin films are deposited using the deposition parameters such as the compositional ratio of the precursor solution and the substrate temperature. The deposited $CuInS_2$ thin films will be analyzed in terms of deposition rate, crystal structure, and optical properties.