模拟分析了有源区不同垒层对380 nm近紫外发光二极管的内量子效率、电子空穴浓度分布、辐射复合效率等产生的影响。有源区垒层材料分别选用GaN、Al0.1Ga0.9N、Al0.1Ga0.9N/Al0.15Ga0.85N/Al0.1Ga0.9N, 其中3层AlGaN的厚度比分别为6 nm/8 nm/6 nm和7 nm/6 nm/7 nm。对比分析发现, 与GaN垒层相比, 选用AlGaN系列垒层可以将更多的载流子限制在有源区内, 空穴浓度可以提高近一个数量级, 辐射复合效率可以提高2~10倍; 3层AlGaN垒层相对于单一AlGaN垒层, 载流子分布更加均匀, 辐射复合效率可以提高7倍以上, 内量子效率可以提高14.5%; 采用不同厚度比的3层AlGaN垒层结构可以微调能带的倾斜程度, 进一步减小极化效应。可以调节合适的厚度比减小极化效应对于载流子分布及内量子效率的影响。

The influence of multiple quantum wells with different barriers on the characteristics of the near ultraviolet light emitting diodes was numerically investigated. Using single GaN, single Al0.1Ga0.9N, trilaminar Al0.1Ga0.9N/Al0.15Ga0.85N/Al0.1Ga0.9N as barriers to study the characteristics of internal quantum efficiency, carriers concentration and radiative recombination rate. For trilaminar Al0.1Ga0.9N/ Al0.15Ga0.85N/Al0.1Ga0.9N barrier, choose two different thickness ratio, 6 nm/8 nm/6 nm and 7 nm/6 nm/7 nm. The simulation results show that LEDs with AlGaN barriers have better performance than GaN barrier LED. For AlGaN barrier LEDs, more carriers can be confined in active region, especially hole concentration, can improve one order of magnitude approximately. The radiative recombination rate can increase 2～10 times. Compared with single AlGaN barrier LED, in trilaminar AlGaN barrier LEDs the carriers concentration is more uniform. And the radiative recombination rate increases about 7 times, the internal quantum efficiency improves 14.5%. The different thickness ratio of trilaminar AlGaN barrier LED can fine adjust the inclination of energy band, then reduce the negative effects on carriers concentration and internal efficiency caused by polarization.