Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution...Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution in the QD-like islands,strain modulation on the InGaN active layers by using the GaN island capping is employed to form an increased surface potential barrier around the dislocation cores,which inhibits the carrier transport to the surrounding dislocations.Cathodoluminescence shows distinct double-peak emissions at 503nm and 444nm,corresponding to the In-rich QD-like emission and the normal quantum well emission,respectively.The QD-like emission becomes dominated in photoluminescence due to the carrier localization effect of In-rich InGaN QDs at relatively low “carrier injection current”.Accordingly,green emission may be enhanced by the following origins:(1) reduction in pits/dislocations density,(2) carrier localization and strain reduction in QDs,(3) strain modulation by GaN island capping,(4) enhanced light extraction with faceted GaN islands on the surface.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60876008 and 61076091the Program for New Century Excellent Talents in Fujian Province University.
文摘Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution in the QD-like islands,strain modulation on the InGaN active layers by using the GaN island capping is employed to form an increased surface potential barrier around the dislocation cores,which inhibits the carrier transport to the surrounding dislocations.Cathodoluminescence shows distinct double-peak emissions at 503nm and 444nm,corresponding to the In-rich QD-like emission and the normal quantum well emission,respectively.The QD-like emission becomes dominated in photoluminescence due to the carrier localization effect of In-rich InGaN QDs at relatively low “carrier injection current”.Accordingly,green emission may be enhanced by the following origins:(1) reduction in pits/dislocations density,(2) carrier localization and strain reduction in QDs,(3) strain modulation by GaN island capping,(4) enhanced light extraction with faceted GaN islands on the surface.
