In this paper, we investigate the effect of pressure on the growth mode of high quality （10-11） GaN using an epi- taxial lateral over growth （ELO） technique by metal organic chemical vapor deposition （MOCVD）. Tw...In this paper, we investigate the effect of pressure on the growth mode of high quality （10-11） GaN using an epi- taxial lateral over growth （ELO） technique by metal organic chemical vapor deposition （MOCVD）. Two pressure growth conditions, high pressure （HP） 1013 mbar and low pressure growth （LP） 500 mbar, are employed during growth. In the high pressure growth conditions, the crystal quality is improved by decreasing the dislocation and stack fault density in the strip connection locations. The room temperature photoluminescence measurement also shows that the light emission intensity increases three times using the HP growth condition compared with that using the LP growth conditions. In the low temperature （77 K） photoluminescence, the defects-related peaks are very obvious in the low pressure growth samples. This result also indicates that the crystal quality is improved using the high pressure growth conditions.展开更多
Semi-polar （1 - 101 ） InGaN/GaN light-emitting diodes were prepared on standard electronic-grade Si （100） substrates. Micro-stripes of GaN and InGaN/GaN quantum wells on semi-polar facets were grown on intersectin...Semi-polar （1 - 101 ） InGaN/GaN light-emitting diodes were prepared on standard electronic-grade Si （100） substrates. Micro-stripes of GaN and InGaN/GaN quantum wells on semi-polar facets were grown on intersecting { 111 } planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. In-situ optical reflectivity and curvature measurements demonstrate that the effect of the thermal expansion coefficient mismatch was greatly reduced. A cross-sectional analysis reveals low threading dislocation density on the top of most surfaces. On such prepared （1-101） GaN, an InGaN/GaN LED was fabricated. Electroluminescence over 5 mA to 60 mA is found with a much lower blue-shift than that on the c-plane device. Such structures therefore could allow higher efficiency light emitters with a weak quantum confined Stark effect throughout the visible spectrum.展开更多
We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask. Transmission electron microscopy, scanning electron microscopy...We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask. Transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy are used to reveal the effect of SiN on the overgrown a-plane GaN growth. The SiN layer effectively terminates the propagation of the threading dislocation and basal plane stacking faults during a-plane GaN regrowth through the interlayer, resulting in the window region shrinking from a rectangle to a ＂black hole＂. Furthermore, strong yellow luminescence （YL） in the nonpolar plane and very weak YL in the semipolar plane on the GaN grain is revealed by cathodoluminescence, suggesting that C-involved defects are responsible for the YL.展开更多
High indium semipolar（1122） and polar（0001） In Ga N layers each with a thickness of about 100 nm are realized simultaneously on sapphire substrates by pulsed metal organic chemical vapor deposition（MOCVD）. The m...High indium semipolar（1122） and polar（0001） In Ga N layers each with a thickness of about 100 nm are realized simultaneously on sapphire substrates by pulsed metal organic chemical vapor deposition（MOCVD）. The morphology evolution, structural and optical characteristics are also studied. The indium content in the layer of the surface（1122）is larger than that of the surface（0001）, which is confirmed by reciprocal space map, photoluminescence spectrum and secondary ion mass spectrometer. Additionally, the（0001） surface with island-like morphology shows inhomogeneous indium incorporation, while the（1122） surface with a spiral-like morphology shows a better homogeneous In composition.This feature is also demonstrated by the monochromatic cathodoluminescence map.展开更多
The effect of a self-organized SiNs interlayer on the defect density of （1122） semipolar GaN grown on 7n-plane sapphire is studied by transmission electron microscopy, atomic force microscopy and high resolution x-r...The effect of a self-organized SiNs interlayer on the defect density of （1122） semipolar GaN grown on 7n-plane sapphire is studied by transmission electron microscopy, atomic force microscopy and high resolution x-ray diffrac- tion. The SiNx interlayer reduces the c-type dislocation density from 2.5 ×10^10 cm^-2 to 5 ×10^8 cm 2. The SiNx interlayer produces regions that are free from basal plane stacking faults （BSFs） and dislocations. The overall BSF density is reduced from 2.1×10^5 cm-1 to 1.3×10^4 cm^-1. The large dislocations and BSF reduction in semipolar （1122） GaN with the SiNx, interlayer result from two primary mechanisms. The first mechanism is the direct dislocation blocking by the SiNx interlayer, and the second mechanism is associated with the unique structure character of （1122） semipolar GaN.展开更多
基金support by the National High Technology Research and Development Program of China(Green Laser)
文摘In this paper, we investigate the effect of pressure on the growth mode of high quality （10-11） GaN using an epi- taxial lateral over growth （ELO） technique by metal organic chemical vapor deposition （MOCVD）. Two pressure growth conditions, high pressure （HP） 1013 mbar and low pressure growth （LP） 500 mbar, are employed during growth. In the high pressure growth conditions, the crystal quality is improved by decreasing the dislocation and stack fault density in the strip connection locations. The room temperature photoluminescence measurement also shows that the light emission intensity increases three times using the HP growth condition compared with that using the LP growth conditions. In the low temperature （77 K） photoluminescence, the defects-related peaks are very obvious in the low pressure growth samples. This result also indicates that the crystal quality is improved using the high pressure growth conditions.
文摘Semi-polar （1 - 101 ） InGaN/GaN light-emitting diodes were prepared on standard electronic-grade Si （100） substrates. Micro-stripes of GaN and InGaN/GaN quantum wells on semi-polar facets were grown on intersecting { 111 } planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. In-situ optical reflectivity and curvature measurements demonstrate that the effect of the thermal expansion coefficient mismatch was greatly reduced. A cross-sectional analysis reveals low threading dislocation density on the top of most surfaces. On such prepared （1-101） GaN, an InGaN/GaN LED was fabricated. Electroluminescence over 5 mA to 60 mA is found with a much lower blue-shift than that on the c-plane device. Such structures therefore could allow higher efficiency light emitters with a weak quantum confined Stark effect throughout the visible spectrum.
基金Project supported by the Fundamental Research Funds for the Central Universities,China (Grant No. K50511250002)the National Key Science and Technology Special Project,China (Grant No. 2008ZX01002-002)the National Natural Science Foundation of China (Grant Nos. 60736033,60976068,and 61076097)
文摘We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask. Transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy are used to reveal the effect of SiN on the overgrown a-plane GaN growth. The SiN layer effectively terminates the propagation of the threading dislocation and basal plane stacking faults during a-plane GaN regrowth through the interlayer, resulting in the window region shrinking from a rectangle to a ＂black hole＂. Furthermore, strong yellow luminescence （YL） in the nonpolar plane and very weak YL in the semipolar plane on the GaN grain is revealed by cathodoluminescence, suggesting that C-involved defects are responsible for the YL.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61204006 and 61574108)the Fundamental Research Funds for the Central Universities,China(Grant No.7214570101)
文摘High indium semipolar（1122） and polar（0001） In Ga N layers each with a thickness of about 100 nm are realized simultaneously on sapphire substrates by pulsed metal organic chemical vapor deposition（MOCVD）. The morphology evolution, structural and optical characteristics are also studied. The indium content in the layer of the surface（1122）is larger than that of the surface（0001）, which is confirmed by reciprocal space map, photoluminescence spectrum and secondary ion mass spectrometer. Additionally, the（0001） surface with island-like morphology shows inhomogeneous indium incorporation, while the（1122） surface with a spiral-like morphology shows a better homogeneous In composition.This feature is also demonstrated by the monochromatic cathodoluminescence map.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61204006 and 61574108the Fundamental Research Funds for the Central Universities under Grant No JB141101the Foundation of Key Laboratory of Nanodevices and Applications of Suzhou Institute of Nano-Tech and Nano-Bionics of Chinese Academy of Sciences under Grant No 15CS01
文摘The effect of a self-organized SiNs interlayer on the defect density of （1122） semipolar GaN grown on 7n-plane sapphire is studied by transmission electron microscopy, atomic force microscopy and high resolution x-ray diffrac- tion. The SiNx interlayer reduces the c-type dislocation density from 2.5 ×10^10 cm^-2 to 5 ×10^8 cm 2. The SiNx interlayer produces regions that are free from basal plane stacking faults （BSFs） and dislocations. The overall BSF density is reduced from 2.1×10^5 cm-1 to 1.3×10^4 cm^-1. The large dislocations and BSF reduction in semipolar （1122） GaN with the SiNx, interlayer result from two primary mechanisms. The first mechanism is the direct dislocation blocking by the SiNx interlayer, and the second mechanism is associated with the unique structure character of （1122） semipolar GaN.
