The Experts below are selected from a list of 309192 Experts worldwide ranked by ideXlab platform
Russell J Hemley - One of the best experts on this subject based on the ideXlab platform.
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recent advances in High Growth Rate single crystal cvd diamond
Diamond and Related Materials, 2009Co-Authors: Qi Liang, Chihshiue Yan, Yufei Meng, Joseph Lai, Szczesny Krasnicki, Hokwang Mao, Russell J HemleyAbstract:There have been important advances in microwave plasma chemical vapor deposition (MPCVD) of large single-crystal CVD diamond at High Growth Rates and applications of this diamond. The types of gas chemistry and Growth conditions, including microwave power, pressure, and substRate surface temperatures, have been varied to optimize diamond quality and Growth Rates. The diamond has been characterized by a variety of spectroscopic and diffraction techniques. We have grown single-crystal CVD diamond over ten carats and above 1 cm in thickness at Growth Rates of 50-100 {micro}m/h. Colorless and near colorless single crystals up to two carats have been produced by further optimizing the process. The nominal Vickers fracture toughness of this High-Growth Rate diamond can be tuned to exceed 20 MPa m{sup 1/2} in comparison to 5-10 MPa m{sup 1/2} for conventional natural and CVD diamond. Post-Growth High-pressure/High-temperature (HPHT) and low-pressure/High-temperature (LPHT) annealing have been carried out to alter the optical, mechanical, and electronic properties. Most recently, single-crystal CVD diamond has been successfully annealed by LPHT methods without graphitization up to 2200 C and < 300 Torr for periods of time ranging from a fraction of minute to a few hours. Significant changes observed in UV, visible, infrared, and photoluminescencemore » spectra are attributed to changes in various vacancy centers and extended defects.« less
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very High Growth Rate chemical vapor deposition of single crystal diamond
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Chihshiue Yan, Hokwang Mao, Yogesh K Vohra, Russell J HemleyAbstract:Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of High-quality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to that of High-pressure, High-temperature synthetic diamond. In addition, the crystals can be produced at Growth Rates from 50 to 150 μm/h, which is up to 2 orders of magnitude Higher than standard processes for making polycrystalline MPCVD diamond. This High-quality single-crystal MPCVD diamond may find numerous applications in electronic devices as High-strength windows and in a new generation of High-pressure instruments requiring large single-crystal anvils.
Zhitao Chen - One of the best experts on this subject based on the ideXlab platform.
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Growth of High quality AlN/sapphire templates with High Growth Rate using a medium-temperature layer
Superlattices and Microstructures, 2019Co-Authors: Wu Hualong, Wei Zhao, He Chenguang, Kang Zhang, He Longfei, Zhitao ChenAbstract:Abstract In this work, crack-free 3.3-μm-thick AlN films with High crystalline quality and atomic smooth surfaces were achieved on sapphire substRates at a High Growth Rate of 2.9 μm/h. Double-axis x-ray rocking curves showed a full width at half maximum of 315 and 419 arc sec for (0002) and (10 1 ¯ 2) reflections, respectively, corresponding to a total threading dislocation (TD) density of 9.79 × 108 cm−2. Cracks were suppressed and crystalline quality was improved by introducing a medium-temperature (MT) layer. It was found that the density of both screw- and edge-type TDs could be significantly reduced by introducing the MT-AlN layer under appropriate temperature. The crystalline improvement is attributed to the delayed coalescence of the AlN islands and Higher probability for the annihilations of TDs by the MT-AlN layer under appropriate temperature. This method provides a promising way in growing practical thick AlN templates suitable for large-scale industrial production.
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Growth of High quality aln sapphire templates with High Growth Rate using a medium temperature layer
Superlattices and Microstructures, 2019Co-Authors: Wei Zhao, Kang Zhang, Zhitao ChenAbstract:Abstract In this work, crack-free 3.3-μm-thick AlN films with High crystalline quality and atomic smooth surfaces were achieved on sapphire substRates at a High Growth Rate of 2.9 μm/h. Double-axis x-ray rocking curves showed a full width at half maximum of 315 and 419 arc sec for (0002) and (10 1 ¯ 2) reflections, respectively, corresponding to a total threading dislocation (TD) density of 9.79 × 108 cm−2. Cracks were suppressed and crystalline quality was improved by introducing a medium-temperature (MT) layer. It was found that the density of both screw- and edge-type TDs could be significantly reduced by introducing the MT-AlN layer under appropriate temperature. The crystalline improvement is attributed to the delayed coalescence of the AlN islands and Higher probability for the annihilations of TDs by the MT-AlN layer under appropriate temperature. This method provides a promising way in growing practical thick AlN templates suitable for large-scale industrial production.
Chihshiue Yan - One of the best experts on this subject based on the ideXlab platform.
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recent advances in High Growth Rate single crystal cvd diamond
Diamond and Related Materials, 2009Co-Authors: Qi Liang, Chihshiue Yan, Yufei Meng, Joseph Lai, Szczesny Krasnicki, Hokwang Mao, Russell J HemleyAbstract:There have been important advances in microwave plasma chemical vapor deposition (MPCVD) of large single-crystal CVD diamond at High Growth Rates and applications of this diamond. The types of gas chemistry and Growth conditions, including microwave power, pressure, and substRate surface temperatures, have been varied to optimize diamond quality and Growth Rates. The diamond has been characterized by a variety of spectroscopic and diffraction techniques. We have grown single-crystal CVD diamond over ten carats and above 1 cm in thickness at Growth Rates of 50-100 {micro}m/h. Colorless and near colorless single crystals up to two carats have been produced by further optimizing the process. The nominal Vickers fracture toughness of this High-Growth Rate diamond can be tuned to exceed 20 MPa m{sup 1/2} in comparison to 5-10 MPa m{sup 1/2} for conventional natural and CVD diamond. Post-Growth High-pressure/High-temperature (HPHT) and low-pressure/High-temperature (LPHT) annealing have been carried out to alter the optical, mechanical, and electronic properties. Most recently, single-crystal CVD diamond has been successfully annealed by LPHT methods without graphitization up to 2200 C and < 300 Torr for periods of time ranging from a fraction of minute to a few hours. Significant changes observed in UV, visible, infrared, and photoluminescencemore » spectra are attributed to changes in various vacancy centers and extended defects.« less
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very High Growth Rate chemical vapor deposition of single crystal diamond
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Chihshiue Yan, Hokwang Mao, Yogesh K Vohra, Russell J HemleyAbstract:Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of High-quality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to that of High-pressure, High-temperature synthetic diamond. In addition, the crystals can be produced at Growth Rates from 50 to 150 μm/h, which is up to 2 orders of magnitude Higher than standard processes for making polycrystalline MPCVD diamond. This High-quality single-crystal MPCVD diamond may find numerous applications in electronic devices as High-strength windows and in a new generation of High-pressure instruments requiring large single-crystal anvils.
Hokwang Mao - One of the best experts on this subject based on the ideXlab platform.
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recent advances in High Growth Rate single crystal cvd diamond
Diamond and Related Materials, 2009Co-Authors: Qi Liang, Chihshiue Yan, Yufei Meng, Joseph Lai, Szczesny Krasnicki, Hokwang Mao, Russell J HemleyAbstract:There have been important advances in microwave plasma chemical vapor deposition (MPCVD) of large single-crystal CVD diamond at High Growth Rates and applications of this diamond. The types of gas chemistry and Growth conditions, including microwave power, pressure, and substRate surface temperatures, have been varied to optimize diamond quality and Growth Rates. The diamond has been characterized by a variety of spectroscopic and diffraction techniques. We have grown single-crystal CVD diamond over ten carats and above 1 cm in thickness at Growth Rates of 50-100 {micro}m/h. Colorless and near colorless single crystals up to two carats have been produced by further optimizing the process. The nominal Vickers fracture toughness of this High-Growth Rate diamond can be tuned to exceed 20 MPa m{sup 1/2} in comparison to 5-10 MPa m{sup 1/2} for conventional natural and CVD diamond. Post-Growth High-pressure/High-temperature (HPHT) and low-pressure/High-temperature (LPHT) annealing have been carried out to alter the optical, mechanical, and electronic properties. Most recently, single-crystal CVD diamond has been successfully annealed by LPHT methods without graphitization up to 2200 C and < 300 Torr for periods of time ranging from a fraction of minute to a few hours. Significant changes observed in UV, visible, infrared, and photoluminescencemore » spectra are attributed to changes in various vacancy centers and extended defects.« less
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very High Growth Rate chemical vapor deposition of single crystal diamond
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Chihshiue Yan, Hokwang Mao, Yogesh K Vohra, Russell J HemleyAbstract:Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of High-quality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to that of High-pressure, High-temperature synthetic diamond. In addition, the crystals can be produced at Growth Rates from 50 to 150 μm/h, which is up to 2 orders of magnitude Higher than standard processes for making polycrystalline MPCVD diamond. This High-quality single-crystal MPCVD diamond may find numerous applications in electronic devices as High-strength windows and in a new generation of High-pressure instruments requiring large single-crystal anvils.
Wei Zhao - One of the best experts on this subject based on the ideXlab platform.
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Growth of High quality AlN/sapphire templates with High Growth Rate using a medium-temperature layer
Superlattices and Microstructures, 2019Co-Authors: Wu Hualong, Wei Zhao, He Chenguang, Kang Zhang, He Longfei, Zhitao ChenAbstract:Abstract In this work, crack-free 3.3-μm-thick AlN films with High crystalline quality and atomic smooth surfaces were achieved on sapphire substRates at a High Growth Rate of 2.9 μm/h. Double-axis x-ray rocking curves showed a full width at half maximum of 315 and 419 arc sec for (0002) and (10 1 ¯ 2) reflections, respectively, corresponding to a total threading dislocation (TD) density of 9.79 × 108 cm−2. Cracks were suppressed and crystalline quality was improved by introducing a medium-temperature (MT) layer. It was found that the density of both screw- and edge-type TDs could be significantly reduced by introducing the MT-AlN layer under appropriate temperature. The crystalline improvement is attributed to the delayed coalescence of the AlN islands and Higher probability for the annihilations of TDs by the MT-AlN layer under appropriate temperature. This method provides a promising way in growing practical thick AlN templates suitable for large-scale industrial production.
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Growth of High quality aln sapphire templates with High Growth Rate using a medium temperature layer
Superlattices and Microstructures, 2019Co-Authors: Wei Zhao, Kang Zhang, Zhitao ChenAbstract:Abstract In this work, crack-free 3.3-μm-thick AlN films with High crystalline quality and atomic smooth surfaces were achieved on sapphire substRates at a High Growth Rate of 2.9 μm/h. Double-axis x-ray rocking curves showed a full width at half maximum of 315 and 419 arc sec for (0002) and (10 1 ¯ 2) reflections, respectively, corresponding to a total threading dislocation (TD) density of 9.79 × 108 cm−2. Cracks were suppressed and crystalline quality was improved by introducing a medium-temperature (MT) layer. It was found that the density of both screw- and edge-type TDs could be significantly reduced by introducing the MT-AlN layer under appropriate temperature. The crystalline improvement is attributed to the delayed coalescence of the AlN islands and Higher probability for the annihilations of TDs by the MT-AlN layer under appropriate temperature. This method provides a promising way in growing practical thick AlN templates suitable for large-scale industrial production.