In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in...In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in the EBL after Mg-preflow treatment,effectively alleviating the commonly observed efficiency collapse and electrons overflowing at cryogenic temperatures.However,unexpected decline in quantum efficiency is observed after Mg-preflow treatment at room temperature.Our conclusions are drawn such that the efficiency decline is probably the result of different emission positions.Higher Mg doping concentration in the EBL after Mg-preflow treatment will make it easier for a hole to be injected into multiple quantum wells with emission closer to pGaN side through the（8-plane rather than the V-shape pits,which is not favorable to luminous efficiency due to the preferred occurrence of accumulated strain relaxation and structural defects in upper QWs closer to p-GaN.Within this framework,apparently disparate experimental observations regarding electroluminescence properties,in this work,are well reconciled.展开更多
To construct world-class iron and steel enterprises, Baosteel has adopted a strategy of environmental management that emphasizes environmental protection in the low-carbon and ecological manufacturing of steel product...To construct world-class iron and steel enterprises, Baosteel has adopted a strategy of environmental management that emphasizes environmental protection in the low-carbon and ecological manufacturing of steel products. In recent years, Baosteel has developed a series of advanced green refractory technologies （including composite refractory precast blocks with a unique ceramic glaze, and high-thermal-conductivity/high-density silica brick） for use in Baosteel coke ovens. The results of these applications not only reduce production costs and increase production efficiency, but also facilitate clean production by coke ovens. Baosteel＇ s coke oven has become China＇ s leading example of the application of green refractories.展开更多
基金Supported by the National Key R&D Program of China under Grant Nos 2016YFB0400600 and 2016YFB0400601the State Key Program of the National Natural Science of China under Grant No 61334001+2 种基金the Key R&D Program of Jiangxi Province under Grant No 20165ABC28007the Natural Science Foundation of Jiangxi Province under Grant No 20151BAB207053the National Natural Science Foundation of China under Grant No 21405076
文摘In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in the EBL after Mg-preflow treatment,effectively alleviating the commonly observed efficiency collapse and electrons overflowing at cryogenic temperatures.However,unexpected decline in quantum efficiency is observed after Mg-preflow treatment at room temperature.Our conclusions are drawn such that the efficiency decline is probably the result of different emission positions.Higher Mg doping concentration in the EBL after Mg-preflow treatment will make it easier for a hole to be injected into multiple quantum wells with emission closer to pGaN side through the（8-plane rather than the V-shape pits,which is not favorable to luminous efficiency due to the preferred occurrence of accumulated strain relaxation and structural defects in upper QWs closer to p-GaN.Within this framework,apparently disparate experimental observations regarding electroluminescence properties,in this work,are well reconciled.
文摘To construct world-class iron and steel enterprises, Baosteel has adopted a strategy of environmental management that emphasizes environmental protection in the low-carbon and ecological manufacturing of steel products. In recent years, Baosteel has developed a series of advanced green refractory technologies （including composite refractory precast blocks with a unique ceramic glaze, and high-thermal-conductivity/high-density silica brick） for use in Baosteel coke ovens. The results of these applications not only reduce production costs and increase production efficiency, but also facilitate clean production by coke ovens. Baosteel＇ s coke oven has become China＇ s leading example of the application of green refractories.
