The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Hajime Okumura - One of the best experts on this subject based on the ideXlab platform.
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Growth Study of p-Type 4H-SiC with Using Aluminum and Nitrogen Co-Doping by 2-Zone Heating Sublimation Method
Materials Science Forum, 2015Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:p-type SiC crystals doped with aluminum and nitrogen were grown by the Sublimation Method. We found that Al and N co-doping is effective for stabilized growth of p-type 4H-SiC polytype. We studied the relationship of polytype of grown crystals and the condition of Al and N feeding during the crystal growth. p-type 4H-SiC with p~1 x 1018 cm-3 are stably-obtained with this Method.
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growth of low resistivity n type 4h sic bulk crystals by Sublimation Method using co doping technique
Materials Science Forum, 2014Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:The nitrogen (N) and aluminum (Al) co-doped growth of n-type 4H-SiC bulk crystals were performed by Sublimation Method. In the co-doping growth, we achieved the lowest resistivity of 6.9mWcm, and we also confirmed phenomenon of stacking faults suppression in spite of high N concentration more than 8 x 1019cm-3.
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aln bulk single crystal growth on 6h sic substrates by Sublimation Method
Journal of Crystal Growth, 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Abstract Large and thick AlN bulk single crystals up to 43 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC (0 0 0 1) substrates by the Sublimation Method using a TaC crucible. Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. The quality at the top of the crystal improves as crystal thickness increases along the 〈0 0 0 1〉 direction during growth: a low etch pit density (7×10 4 cm −2 ) and a small full width at half maximum for a 0002 X-ray rocking curve (58 arcsec) have been achieved at a thickness of ∼8 mm. The possible mechanism behind the improvement in the AlN crystal quality is also discussed.
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AlN bulk crystal growth by Sublimation Method
Physica Status Solidi (c), 2010Co-Authors: Tomohisa Kato, Ichiro Nagai, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:In this study, we report the growth of aluminum nitride (AlN) bulk single crystals by the Sublimation Method. The crystals were grown in a newly designed TaC crucible. The crucible has a TaC guard ring around the seed crystal to protect against polycrystal deposition around the seed crystal during the initial growth stage. The ring enhances lateral enlargement growth because it protects against the polycrystal deposition. The (0001) oriented AlN crystals were grown on (0001) SiC and (0001) AlN seed crystals. The largest grown crystal was 43 mm in diameter. The best quality area on the grown AlN crystal had the lowest etch pit density of 1 × 10-4cm-2. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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AlN bulk single crystal growth on SiC and AlN substrates by Sublimation Method
2010 22nd International Conference on Indium Phosphide and Related Materials (IPRM), 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Aluminum nitride (AlN) bulk single crystals up to 45 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC(0001) substrates by the Sublimation Method. Moreover, high growth rate of 200μm/h has been achieved by high temperature homo-epitaxial AlN growth on AlN(0001) substrate. The Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. In both the hetero- and homo-epitaxial AlN bulk single crystal growth, the quality at the top of the crystal improves as the crystal thickness increases along the direction during the growth: low etch pit density 7 × 104 cm-2 and 1 × 104 cm-2 have been achieved at a thickness of 8 mm and 2 mm in the hetero- and homo-epitaxial growth, respectively.
Tomohisa Kato - One of the best experts on this subject based on the ideXlab platform.
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Growth Study of p-Type 4H-SiC with Using Aluminum and Nitrogen Co-Doping by 2-Zone Heating Sublimation Method
Materials Science Forum, 2015Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:p-type SiC crystals doped with aluminum and nitrogen were grown by the Sublimation Method. We found that Al and N co-doping is effective for stabilized growth of p-type 4H-SiC polytype. We studied the relationship of polytype of grown crystals and the condition of Al and N feeding during the crystal growth. p-type 4H-SiC with p~1 x 1018 cm-3 are stably-obtained with this Method.
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growth of low resistivity n type 4h sic bulk crystals by Sublimation Method using co doping technique
Materials Science Forum, 2014Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:The nitrogen (N) and aluminum (Al) co-doped growth of n-type 4H-SiC bulk crystals were performed by Sublimation Method. In the co-doping growth, we achieved the lowest resistivity of 6.9mWcm, and we also confirmed phenomenon of stacking faults suppression in spite of high N concentration more than 8 x 1019cm-3.
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aln bulk single crystal growth on 6h sic substrates by Sublimation Method
Journal of Crystal Growth, 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Abstract Large and thick AlN bulk single crystals up to 43 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC (0 0 0 1) substrates by the Sublimation Method using a TaC crucible. Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. The quality at the top of the crystal improves as crystal thickness increases along the 〈0 0 0 1〉 direction during growth: a low etch pit density (7×10 4 cm −2 ) and a small full width at half maximum for a 0002 X-ray rocking curve (58 arcsec) have been achieved at a thickness of ∼8 mm. The possible mechanism behind the improvement in the AlN crystal quality is also discussed.
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AlN bulk crystal growth by Sublimation Method
Physica Status Solidi (c), 2010Co-Authors: Tomohisa Kato, Ichiro Nagai, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:In this study, we report the growth of aluminum nitride (AlN) bulk single crystals by the Sublimation Method. The crystals were grown in a newly designed TaC crucible. The crucible has a TaC guard ring around the seed crystal to protect against polycrystal deposition around the seed crystal during the initial growth stage. The ring enhances lateral enlargement growth because it protects against the polycrystal deposition. The (0001) oriented AlN crystals were grown on (0001) SiC and (0001) AlN seed crystals. The largest grown crystal was 43 mm in diameter. The best quality area on the grown AlN crystal had the lowest etch pit density of 1 × 10-4cm-2. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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AlN bulk single crystal growth on SiC and AlN substrates by Sublimation Method
2010 22nd International Conference on Indium Phosphide and Related Materials (IPRM), 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Aluminum nitride (AlN) bulk single crystals up to 45 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC(0001) substrates by the Sublimation Method. Moreover, high growth rate of 200μm/h has been achieved by high temperature homo-epitaxial AlN growth on AlN(0001) substrate. The Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. In both the hetero- and homo-epitaxial AlN bulk single crystal growth, the quality at the top of the crystal improves as the crystal thickness increases along the direction during the growth: low etch pit density 7 × 104 cm-2 and 1 × 104 cm-2 have been achieved at a thickness of 8 mm and 2 mm in the hetero- and homo-epitaxial growth, respectively.
Isamu Akasaki - One of the best experts on this subject based on the ideXlab platform.
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High-speed high-quality epitaxial growth of N and B codoped 6H-SiC by closed Sublimation Method
MRS Proceedings, 2020Co-Authors: Tomohiko Maeda, Motoaki Iwaya, Satoshi Kamiyama, Isamu Akasaki, Hiroshi Amano, Yoshihiro Nakamura, Tomoaki Furusho, Hiroyuki Kinoshita, Masahiro YoshimotoAbstract:ABSTRACTN and B codoped 6H-SiC epilayers were grown by the closed Sublimation Method, the growth rate of which was as high as 100 mm/h. Donor acceptor (DA) pair emission at different temperatures was investigated for two samples with different B concentrations. The integrated photon count obtained from the photoluminescence (PL) spectra of the sample having high B concentration increases with temperature. To estimate the internal quantum efficiency, we measured the PL integrated photon counts of GaN at 10 K as a reference. The integrated PL photon count of 6H-SiC DA-doped epilayer at 250 K is almost comparable to that of GaN at 10 K, which is thought to be almost 100% because of the freezing of the nonradiative recombination at low temperature. This result implies that the internal quantum efficiency of the 6H-SiC DA-doped epilayer exceeds 95%.
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freestanding highly crystalline single crystal aln substrates grown by a novel closed Sublimation Method
Applied Physics Express, 2011Co-Authors: Masayasu Yamakawa, Kazuki Murata, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki, Hiroshi Amano, Masanobu AzumaAbstract:We fabricated thick freestanding AlN films by a novel close-spaced Sublimation Method. The spacing between a sintered AlN polycrystal and a SiC substrate is 1 mm. A Ta ring was used to control the spacing between the AlN polycrystal and the SiC substrate. In addition, a special AlN adhesive was also used to fill in the gap between the AlN polycrystal, the Ta ring, and the SiC substrate. By a combination of these techniques, an AlN growth rate as high as 600 µm/h was achieved. A freestanding AlN layer was obtained by the Sublimation of the SiC substrate during the AlN growth.
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6H-SiC Homoepitaxial Growth and Optical Property of Boron- and Nitrogen-Doped Donor-Acceptor Pair (DAP) Emission of 1º-Off Substrate by Closed-Space Sublimation Method
Materials Science Forum, 2006Co-Authors: Yohjiro Kawai, Motoaki Iwaya, Satoshi Kamiyama, Isamu Akasaki, Hiroshi Amano, Tomohiko Maeda, Yoshihiro Nakamura, Masahiro Yoshimoto, Yoji Sakurai, Tomoaki FurushoAbstract:We demonstrate high-speed and high-quality 6H-SiC homoepitaxial growth on a 1°-off c-plane SiC substrate by a closed-space Sublimation Method. By optimizing the size of single-crystal source materials in the growth system, a high-quality 6H-SiC epilayer with an X-ray diffraction rocking curve (0006) full-width at the half maximum (FWHM) of 38 arcsec was obtained. We also carried out doping of nitrogen and boron during the growth of the SiC epilayer. A strong donor-acceptor pair (DAP) emission at a peak wavelength of 570 nm under excitation by a 395 nm nitride-based light-emitting diode (LED) was observed. The 6H-SiC with DAP emission is promising for use as a phosphor in a nitride-based LED, because high-quality nitride layers can be grown on the SiC substrates with small off-oriented angles.
Tomonori Miura - One of the best experts on this subject based on the ideXlab platform.
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Growth Study of p-Type 4H-SiC with Using Aluminum and Nitrogen Co-Doping by 2-Zone Heating Sublimation Method
Materials Science Forum, 2015Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:p-type SiC crystals doped with aluminum and nitrogen were grown by the Sublimation Method. We found that Al and N co-doping is effective for stabilized growth of p-type 4H-SiC polytype. We studied the relationship of polytype of grown crystals and the condition of Al and N feeding during the crystal growth. p-type 4H-SiC with p~1 x 1018 cm-3 are stably-obtained with this Method.
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growth of low resistivity n type 4h sic bulk crystals by Sublimation Method using co doping technique
Materials Science Forum, 2014Co-Authors: Tomohisa Kato, Tomonori Miura, Satoru Takagi, Yasushi Urakami, Hiroyuki Kondo, Fusao Hirose, Hajime OkumuraAbstract:The nitrogen (N) and aluminum (Al) co-doped growth of n-type 4H-SiC bulk crystals were performed by Sublimation Method. In the co-doping growth, we achieved the lowest resistivity of 6.9mWcm, and we also confirmed phenomenon of stacking faults suppression in spite of high N concentration more than 8 x 1019cm-3.
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aln bulk single crystal growth on 6h sic substrates by Sublimation Method
Journal of Crystal Growth, 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Abstract Large and thick AlN bulk single crystals up to 43 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC (0 0 0 1) substrates by the Sublimation Method using a TaC crucible. Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. The quality at the top of the crystal improves as crystal thickness increases along the 〈0 0 0 1〉 direction during growth: a low etch pit density (7×10 4 cm −2 ) and a small full width at half maximum for a 0002 X-ray rocking curve (58 arcsec) have been achieved at a thickness of ∼8 mm. The possible mechanism behind the improvement in the AlN crystal quality is also discussed.
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AlN bulk crystal growth by Sublimation Method
Physica Status Solidi (c), 2010Co-Authors: Tomohisa Kato, Ichiro Nagai, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:In this study, we report the growth of aluminum nitride (AlN) bulk single crystals by the Sublimation Method. The crystals were grown in a newly designed TaC crucible. The crucible has a TaC guard ring around the seed crystal to protect against polycrystal deposition around the seed crystal during the initial growth stage. The ring enhances lateral enlargement growth because it protects against the polycrystal deposition. The (0001) oriented AlN crystals were grown on (0001) SiC and (0001) AlN seed crystals. The largest grown crystal was 43 mm in diameter. The best quality area on the grown AlN crystal had the lowest etch pit density of 1 × 10-4cm-2. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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AlN bulk single crystal growth on SiC and AlN substrates by Sublimation Method
2010 22nd International Conference on Indium Phosphide and Related Materials (IPRM), 2010Co-Authors: Ichiro Nagai, Tomohisa Kato, Tomonori Miura, Hiroyuki Kamata, Kunihiro Naoe, Kazuo Sanada, Hajime OkumuraAbstract:Aluminum nitride (AlN) bulk single crystals up to 45 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC(0001) substrates by the Sublimation Method. Moreover, high growth rate of 200μm/h has been achieved by high temperature homo-epitaxial AlN growth on AlN(0001) substrate. The Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. In both the hetero- and homo-epitaxial AlN bulk single crystal growth, the quality at the top of the crystal improves as the crystal thickness increases along the direction during the growth: low etch pit density 7 × 104 cm-2 and 1 × 104 cm-2 have been achieved at a thickness of 8 mm and 2 mm in the hetero- and homo-epitaxial growth, respectively.
Kwang-joon Hong - One of the best experts on this subject based on the ideXlab platform.
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Growth of Zinc Selenide Single Crystal by the Sublimation Method
2020Co-Authors: Y.j. Shin, P.y. Yu, T. S. Jeong, C. T. Choi, Kwang-joon HongAbstract:A zinc selenide (ZnSe) single crystal has been grown by using the Sublimation Method without a seed crystal in a two-stage vertical furnace using a reservoir. The temperature dierence, 10 C, between the source and the growth parts in the growth tube was in good agreement with the calculated value of 9.99 C. From the measurement of the Hall eect, it was found that the as-grown ZnSe single crystal was a semi-insulator like p-type with a room temperature resistivity of 10 8 cm, a carrier concentration of 10 6 holes cm 3 , and a mobility of 10 3 cm 2 /V sec. However, the ZnSe single crystal annealed in a molten Zn solution was found to be a conductive n-type with room temperature resistivity of 10 0 cm, a carrier concentration of 10 15 electrons cm 3 , and a mobility of 10 2 cm 2 /V sec. The energy band gap obtained from photocurrent (PC) measurements follows Varshni’s equation Eg(T ) = 2.808 eV (8.690 10 4 eV/K)T 2 /(T + 330).
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the optical properties of cds crystal grown by the Sublimation Method
Journal of Crystal Growth, 2000Co-Authors: Kwang-joon Hong, Tak Jeong, C J Yoon, Y.j. ShinAbstract:Abstract A cadmium sulfide (CdS) single crystal was grown by the Sublimation Method without a seed crystal in a two-stage vertical electric furnace. The carrier concentration and mobility obtained from Hall measurements at room temperature were 2.90 ×10 16 cm −3 and 316 cm 2 /V s, respectively. The photoluminescence and the photocurrent measurement of the CdS single crystal have been performed in the temperature ranging from 20 to 293 K. From the photoluminescence measurement, the energy of the free exciton Ex(A) and Ex(B) has been obtained to be 2.5511 and 2.5707 eV, respectively. The variance of the peak position, intensity, and linewidth of the free excitons as a function of the temperature have been investigated by means of the conventional empirical relations and Toyozawa's theory. The crystal field of the CdS and its splitting energy, Δ c r , have been found to be 19.6 meV. In the photocurrent measurement, only the Ex(A) exciton peak has been observed. The energy band gap of the CdS at room temperature was determined to be 2.4749 eV by the photoluminescence and photocurrent measurement. Also, the temperature dependence of the energy band gap of the CdS, E g ( T ), has been examined.
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Growth of zinc selenide single crystal by the modified Piper and Polich Sublimation Method
Journal of Crystal Growth, 1998Co-Authors: T. S. Jeong, P.y. Yu, Kwang-joon Hong, H.g. An, C.j. Youn, Y.j. ShinAbstract:Abstract A high-quality zinc selenide (ZnSe) single crystal was grown in a two-stage vertical electric furnace by the Piper and Polich Sublimation Method with an asymmetric temperature profile around a peak temperature. The growth of the single crystal was optimized at the temperature difference of 13°C between the source and growth parts in the growth tube. The temperature difference was in good agreement with the calculated value of 135.018°C. The diffraction patterns shows that the single crystal exhibits a zinc blende structure with a lattice constant of 5.627 A. The measured carrier concentration and mobility of the as-grown ZnSe single crystal are 4.92×10 8 holes cm −3 and 4.40×10 3 cm 2 /V s at room temperature, respectively. We notice that the energy band gap obtained from photocurrent measurements follows Varshni's formula E g (T)=2.808 eV −(8.69×10 −4 eV/K ){T 2 /(T+330)} rather than a linear relationship E g (T)=2.83 eV −(8.0×10 −4 eV/K )T .
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Growth of cadmium sulfide single crystal by the Sublimation Method
Journal of Crystal Growth, 1995Co-Authors: Tak Jeong, P.y. Yu, Y.j. Shin, H.k. Shin, Kwang-joon HongAbstract:A cadmium sulfide (CdS) single crystal was grown by the Sublimation Method without a seed crystal in a two-stage vertical electric furnace. The temperature difference, 15°C, between the source and growth parts in the growth tube was in good agreement with the calculated value of 14.7°C. From the diffraction patterns, the single crystal exhibits a hexagonal structure and its c-axis is along the symmetry axis of the growth tube. The measured carrier concentration and mobility of the CdS single crystal are about 2.90 × 1016 cm−3 and 316 cm2/V·s, respectively, at room temperature. The energy bandgap obtained from photocurrent measurements follows Varshni's equation Eg(T) = 2.552 eV − (5.75 × 10−3 eV)T2(T + 3743) rather than a linear relationship Eg(T) = 2.58 eV − (5.24 × 10−4 eVK)T.
