Carrier Manipulation and Performance Enhancement of N-polar AlGaN-based LED with Grading Quantum Barriers

The National Key Research and Development Program of China (Nos. 2016YFB0400803, 2016YFB0400802, 2017YFB0404202), the National Natural Sciences Foundation of China (Nos. 61527814, 61674147, U1505253), Beijing Nova Program (No. Z181100006218007), Youth Innovation Promotion Association CAS (No. 2017157), King Abdullah University of Science and Technology (KAUST) Baseline (No. BAS/1/1664-01-01), KAUST Competitive Research Grant (Nos. URF/1/3437-01-01, URF/1/3771-01-01), KAUST GCC (No. REP/1/3189-01-01), National Natural Science Foundation of China (No. 61774065).