Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, ...Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, etched method and atomic force microscope (AFM). Growth mechanism of AlN crystal grown on heterogeneous SiC seeds was proposed. Crystallization quality of AlN samples were improved with the growth process, which is associated with the growth mechanism. AlN single wafer has excellent crystallization quality, which is indicated by HRXRD showing the (0002),(1012) XRD FWHM of 76.3,52.5 arcsec, respectively. The surface of the AlN wafer is measured by AFM with a roughnessof 0.15 nm, which is a promising seed for AlN homogeneous growth.展开更多
AlN single crystal grown by physical vapor transport (PVT) using homogeneous seed is considered as the most promising approach to obtain high-quality AlN boule.In this work,the morphology of AlN single crystals grown ...AlN single crystal grown by physical vapor transport (PVT) using homogeneous seed is considered as the most promising approach to obtain high-quality AlN boule.In this work,the morphology of AlN single crystals grown under different modes (3D islands and single spiral center) were investigated.It is proved that,within an optimized thermal distribution chamber system,the surface temperature of AlN seed plays an important role in crystal growth,revealing a direct relationship between growth mode and growth condition.Notably,a high-quality AlN crystal,with (002) and (102) reflection peaks of 65and 36 arcsec at full width at half maximum (FWHM),was obtained grown under a single spiral center mode.And on which,a high-quality Al_x Ga_(1–x) N epitaxial layer with high Al content (x=0.54) was also obtained.The FWHMs of (002) and (102) reflection of Al_x Ga_(1–x) N were 202 and 496 arcsec,respectively,which shows superiority over their counterpart grown on SiC or a sapphire substrate.展开更多
β-GaOis an ultra-wide band-gap semiconductor with promising applications in UV optical detectors,Schottky barrier diodes, field-effect transistors and substrates for light-emitting diodes. However, the preparation of...β-GaOis an ultra-wide band-gap semiconductor with promising applications in UV optical detectors,Schottky barrier diodes, field-effect transistors and substrates for light-emitting diodes. However, the preparation of large β-GaOcrystals is undeveloped and many properties of this material have not been discovered yet. In this work, 2-inch β-GaOsingle crystals were grown by using an edge-defined film-fed growth method. The high quality of the crystal has been proved by high-resolution X-ray diffraction with 19.06 arcsec of the full width at half maximum. The electrical properties and optical properties of both the unintentionally doped and Si-doped β-GaOcrystals were investigated systematically.展开更多
A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoel...A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoelectron spectroscopy（XPS）,high resolution transmission electron microscopy（HRTEM） detection show that high quality AIN nanowires were prepared. Nanostructures including nanorings, nanosprings, nanohelices, chainlike nanowires, six-fold symmetric nanostructure and rod-like structure were successfully obtained by controlling the growth duration and temperature. The morphology evolution was attributed to electrostatic polar charge model and the crystalline lattice structure of AIN.展开更多
基金supported by National Key Research and Development Plan of China (No. 2017YFB0404103)National Natural Science Foundation of China (No. 51702297)Tianjin Science and Technology Plan Project (No. 17YFZCGX00520)
文摘Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, etched method and atomic force microscope (AFM). Growth mechanism of AlN crystal grown on heterogeneous SiC seeds was proposed. Crystallization quality of AlN samples were improved with the growth process, which is associated with the growth mechanism. AlN single wafer has excellent crystallization quality, which is indicated by HRXRD showing the (0002),(1012) XRD FWHM of 76.3,52.5 arcsec, respectively. The surface of the AlN wafer is measured by AFM with a roughnessof 0.15 nm, which is a promising seed for AlN homogeneous growth.
基金supported by the National Key Research and Development Plan of China (2017YFB0404103)the National Natural Science Foundation of China (No.51702297)。
文摘AlN single crystal grown by physical vapor transport (PVT) using homogeneous seed is considered as the most promising approach to obtain high-quality AlN boule.In this work,the morphology of AlN single crystals grown under different modes (3D islands and single spiral center) were investigated.It is proved that,within an optimized thermal distribution chamber system,the surface temperature of AlN seed plays an important role in crystal growth,revealing a direct relationship between growth mode and growth condition.Notably,a high-quality AlN crystal,with (002) and (102) reflection peaks of 65and 36 arcsec at full width at half maximum (FWHM),was obtained grown under a single spiral center mode.And on which,a high-quality Al_x Ga_(1–x) N epitaxial layer with high Al content (x=0.54) was also obtained.The FWHMs of (002) and (102) reflection of Al_x Ga_(1–x) N were 202 and 496 arcsec,respectively,which shows superiority over their counterpart grown on SiC or a sapphire substrate.
文摘β-GaOis an ultra-wide band-gap semiconductor with promising applications in UV optical detectors,Schottky barrier diodes, field-effect transistors and substrates for light-emitting diodes. However, the preparation of large β-GaOcrystals is undeveloped and many properties of this material have not been discovered yet. In this work, 2-inch β-GaOsingle crystals were grown by using an edge-defined film-fed growth method. The high quality of the crystal has been proved by high-resolution X-ray diffraction with 19.06 arcsec of the full width at half maximum. The electrical properties and optical properties of both the unintentionally doped and Si-doped β-GaOcrystals were investigated systematically.
基金Project supported by the Natural Science Foundation of Tianjin,China(No.15JCQNJC03700)the National Natural Science Foundation of China(Nos.51702297)
文摘A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoelectron spectroscopy（XPS）,high resolution transmission electron microscopy（HRTEM） detection show that high quality AIN nanowires were prepared. Nanostructures including nanorings, nanosprings, nanohelices, chainlike nanowires, six-fold symmetric nanostructure and rod-like structure were successfully obtained by controlling the growth duration and temperature. The morphology evolution was attributed to electrostatic polar charge model and the crystalline lattice structure of AIN.
