• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.239-242
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• 2004

A stoichiometric mixture of evaporating materials for $CdIn_2S_4$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CdIn_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by hot wall epitaxy(HWE) system. The source and substrate temperatures 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 $CdIn_2S_4$ single crystal thin films measured from Hall effect by van der Pauw method are $9.01{\times}10^{16}\;cm^{-3}$ and $219\;cm^2/V{\cdot}s$ at 293 K, respectively. From the optical absorption measurement, the temperature dependence of energy band gap on $CdIn_2S_4$ single crystal thin films was found to be $E_g(T)\;=\;2.7116\;eV\;-\;(7.74{\times}10^{-4}\;eV)T^2/(T+434)$. After the as-grown $CdIn_2S_4$ single crystal thin films was annealed in Cd-, S-, and In-atmospheres, the origin of point defects of $CdIn_2S_4$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K.

• 한국결정성장학회지
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• 제27권3호
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• pp.105-109
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• 2017

고주파 유도 가열 장치를 이용하여 승화법으로 성장된 AlN 단결정을 질소 분위기 하에서 $1200^{\circ}C$와 $1500^{\circ}C$에서 열처리하였다. 열처리 후 단결정 시편들의 표면을 광학현미경으로 관찰하였으며, DCXRD(Double crystal X-ray Diffractometry)를 이용하여 FWHM(Full width of half maximum) 값을 측정하여 결정성의 변화를 평가하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.154-154
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• 2003

A stoichiometric mixture of evaporating materials for CuGaSe2 single crystal thin films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal CuGaSe2, it was found tetragonal structure whose lattice constant at and co were 5.615 ${\AA}$ and 11.025 ${\AA}$, respectively. To obtain the single crystal thin films, CuGaSe2 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (MWE) system. The source and substrate temperatures were Slot 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 (UXD). The carrier density and mobility of CuGaSe2 single crystal thin films measured with Hall effect by van der Pauw method are 5.0l${\times}$10$\^$17/ cm$\^$-3/ and 245 $\textrm{cm}^2$/V$.$s at 293K, respectively. The temperature dependence of the energy band gap of the CuGaSe2 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 1.7998 eV - (8.7489${\times}$10$\^$-4/ eV/K)T$^2$/(T + 335 K. After the as-grown CuGaSe2 single crystal thin films was annealed in Cu-, Se-, and Ca-atmospheres, the origin of point defects of CuGaSe2 single crystal thin films has been investigated by the photoluminescence(PL) at 10 K The native defects of V$\_$CU/, V$\_$Se/, Cu$\_$int/, and Se$\_$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 CuGaSe2 single crystal thin films to an optical n-type. Also, we confirmed that Ga in CuGaSe2/GaAs did not form the native defects because Ga in CuGaSe2 single crystal thin films existed in the form of stable bonds.

• 한국결정성장학회지
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• 제34권2호
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• pp.61-65
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• 2024

HVPE(Hydride vapor phase epitaxy) 공법은 기체상의 원료를 사용하여 박막 또는 단결정을 제조하는 공법이다. 화학적 기상증착법의 원리를 적용하여 난용융성 또는 고융점의 물질의 단결정을 성장할 수 있는 공법으로서, 질화갈륨(GaN) 단결정을 얻을 수 있는 공법 중 하나이다. 최근 동 공법을 이용하여 질화알루미늄(AlN) 단결정을 성장하고자 하는 연구가 많이 수행되어져 왔으나, 아직은 좋은 결과를 얻지 못하고 있다. 본 연구에서는 AlN 단결정을 HVPE 공법으로 성장하고자 하였다. 성장 공정에서 질소를 운송가스(Carrior gas)로 사용하였으며, 질소(N2)의 양의 변화에 따른 성장 결과를 고찰하여 보았다. 질소의 양이 증가함에 따른 성장 결정의 변화 양상을 확인할 수 있었다. 성장된 AlN 단결정의 형상을 광학 현미경을 사용하여 관찰하였고, 이중결정 X선 회절 분석(DCXRD, Double crystal X-ray diffractometry)을 이용하여, AlN 결정의 생성을 확인함과 동시에 성장된 단결정의 결정성도 알아보았다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.526-526
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• 1996

The single crystal of LiTaO3 is well known eletro-optic material as well as the piezoelectric one applied to SAW filter. LiTaO3 has large electro-optic effects, so applied to optical switch, acosto-optic deflector, and optical memory device using photorefractive effects. The crystal growth of SAW-grade LiTaO3 has been studied many aspects, but there is no detail research about optic-grade crystal growth. The conditions of optic-grade LiTaO3 single crystal are as below. The optical transmittance must be over 75%, and axial and radial concentratiom uniformity below 1%. The variation of Curie temperature depending on Li/Ta ratio must be also below 2$^{\circ}C$ and no internal no internal cracks and defects. Because of the limitation of crystal quality, the growing of optic-grade LiTaO3 single crystal is very difficult compared with the growing of SAW-grade. In this research, upper conditions of optic-grade single crystal was investigated after growing of 1 inch diameter and 1.5 inch length LiTaO3 single crystal having no internal cracks and defects using Czochralski method. Curie temperature was determined with DSC and measuring capacitance and lattice parameter was calculated about the grown crystal and ceramic powder samples of various Li/Ta ratio. The result of Tc variation was below 1.2$^{\circ}C$ all over the grown crystal, so it is confirmed that LiTaO3 was grown under congruent melting composition having optical homogeniety. Also, the optical transmittance was about 78%, which was sufficient for optical device.

• 한국전기전자재료학회논문지
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• 제14권6호
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• pp.445-454
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• 2001

The stochiometric mix of evaporating materials for the CuInSe$_2$ single crystal thin films was prepared from horizontal 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 temperature were 62$0^{\circ}C$ and 41$0^{\circ}C$, 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 CuInSe$_2$ single crystal thin films measured from Hall effect fby van der Pauw method are 9.62x10$^{16}$ cm$^{-3}$ , 296$\textrm{cm}^2$/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 he values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 6.1 meV and 175.2 meV at 10K, respectively. From the photoluminescence measurement on CuInSe$_2$ single crystal thin film we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy of neutral donor bound excition were 7meV and 5.9meV, respectivity. by Haynes rule, an activation energy of impurity was 50 meV.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.163-166
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• 2001

The stochiometric mix of evaporating materials for the $ZnGa_{2}Se_{4}$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $ZnGa_{2}Se_{4}$ 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 $610^{\circ}C$ and $450^{\circ}C$, 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 $ZnGa_{2}Se_{4}$ single crystal trun films measured from Hall effect by van der Pauw method are $9.63{\times}10^{17}cm^{-3}$, $296cm^{2}/V{\cdot}s$ at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c axis of the $ZnGa_{2}Se_{4}$ single crystal thin film, we have found that the values of spin orbit splitting $\Delta$ So and the crystal field splitting $\Delta$Cr were 251.9 meV and 183.2 meV at 10 K, respectively. From the photoluminescence measurement on $ZnGa_{2}Se_{4}$ single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton $(A^{0},X)$ having very strong peak intensity. Then, the full-width-at -half-maximum(FWHM) and binding energy of neutral acceptor bound excition were 11 meV and 24.4 meV, respectivity. By Haynes rule, an activation energy of impurity was 122 meV.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.81-82
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• 2007

The stochiometric mix of evaporating materials for the $CdGa_2Se_4$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CdGa_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $630^{\circ}C\;and\;420^{\circ}C$, respectively. After the as-grown single crystal $CdGa_2Se_4$ thin films were annealed in Cd-, Se-, and Ga -atmospheres, the origin of point defects of single crystal $CdGa_2Se_4$ thin films has been investigated by PL at 10 K. The native defects of $V_{Cd},\;V_{Se},\;Cd_{int},\;and\;Se_{int}$ obtained by PL measurements were classified as donors or acceptors. And we concluded that the heat-treatment in the Cd-atmosphere converted single crystal $CdGa_2Se_4$ thin films to an optical p-type. Also, we confirmed that Ga in $CdGa_2Se_4$/GaAs did not form the native defects because Ga in single crystal $CdGa_2Se_4$ thin films existed in the form of stable bonds.

• 한국초전도ㆍ저온공학회논문지
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• 제1권1호
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• pp.1-6
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• 1999

The microstructures of top seed mult processde $\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_7$.$\delta$ single crystal were studied. Although shape of the seed was not faceted. the growth shape of Y123 single crystal was faceted. It was observed that Y211 phases were trapped in specific spaces of the faceted region. From the microstructural investigation. it was suggested that the segregation of Y211 is due to the difference of growth rates in crystal direction. When a single crystal was grown by the single seed with stepped multi surfaces. a microstrue was grown from multi-seed. The microstructure show the possibility of multi-seed growth. Corn kernel like structure without Y211 phase was observed and seemed to be formed by the diffusion reaction between Y211 phase in crystal and liquid wetted on the crystal. the diagonal line on Y123 crystal was observed that it was formed by the corn kernel like structure.