摘要
Ga N micro-pyramids with AlGaN capping layer are grown by selective metal–organic–vapor phase epitaxy（MOVPE）. Compared with bare Ga N micro-pyramids, AlGaN/Ga N micro-pyramids show wrinkling morphologies at the bottom of the structure. The formation of those special morphologies is associated with the spontaneously formed AlGaN polycrystalline particles on the dielectric mask, owing to the much higher bond energy of Al–N than that of Ga–N. When the sizes of the polycrystalline particles are larger than 50 nm, the uniform source supply behavior is disturbed, thereby leading to unsymmetrical surface morphology. Analysis reveals that the scale of surface wrinkling is related to the migration length of Ga adatoms along the AlGaN {1ī01} facet. The migration properties of Al and Ga further affect the distribution of Al composition along the sidewalls, characterized by the μ-PL measurement.
Ga N micro-pyramids with AlGaN capping layer are grown by selective metal–organic–vapor phase epitaxy（MOVPE）. Compared with bare Ga N micro-pyramids, AlGaN/Ga N micro-pyramids show wrinkling morphologies at the bottom of the structure. The formation of those special morphologies is associated with the spontaneously formed AlGaN polycrystalline particles on the dielectric mask, owing to the much higher bond energy of Al–N than that of Ga–N. When the sizes of the polycrystalline particles are larger than 50 nm, the uniform source supply behavior is disturbed, thereby leading to unsymmetrical surface morphology. Analysis reveals that the scale of surface wrinkling is related to the migration length of Ga adatoms along the AlGaN {1ī01} facet. The migration properties of Al and Ga further affect the distribution of Al composition along the sidewalls, characterized by the μ-PL measurement.
基金
supported by the National Natural Science Foundation of China(Grant Nos.61274039 and 61574173)
the National Key Research and Development Program,China(Grant No.2016YFB0400105)
the International Science and Technology Collaboration Program of Guangdong Province,China(Grant No.2013B051000041)
the International Science and Technology Collaboration Program of Guangzhou City,China(Grant No.2016201604030055)
the National High Technology Research and Development Program of China(Grant No.2014AA032606)
Guangdong Provincial Natural Science Foundation,China(Grant No.2015A030312011)
the Science&Technology Plan of Guangdong Province,China(Grant Nos.2015B090903062,2015B010132007,and2015B010129010)
the Science and Technology Plan of Guangzhou,China(Grant No.201508010048)
the Science and Technology Plan of Foshan,China(Grant No.201603130003)
Guangdong–Hong Kong Joint Innovation Project of Guangdong Province,China(Grant No.2014B050505009)
the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2014KF17)
the Zhuhai Key Technology Laboratory of Wide Bandgap Semiconductor Power Electronics,Sun Yat-sen University(Grant No.20167612042080001)
