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In Ga N/Ga N多量子阱中由于存在极化效应导致能带弯曲,并由此导致电子和空穴在空间上被分离,因此严重降低了Ga N基LED的发光效率.针对此问题,我们设计了一种组分渐变的量子阱结构,利用组分与能带的关系对量子阱进行能带调控,使得量子阱中的能带弯曲减弱.该方法有效增加了LED的光功率和外量子效率.电致发光谱测试显示,在注入电流为35 A/cm2时,具有能带调控量子阱的LED其外量子效率比传统结构的LED提高了10.6%,发光功率提高了9.8%.能带模拟显示,能带调控后的量子阱中能带倾斜现象减弱,且空穴浓度明显增加,因此电子空穴波函数在空间中的重叠面积得到有效提高,最终提高了辐射复合效率.
InGaN / GaN multiple quantum wells due to the polarization effect of the band bending, and thus lead to the electron and hole are spatially separated, thus seriously reducing the Ga N-based LED luminous efficiency.In response to this problem, We design a graded quantum well structure, using the relationship between the composition and the energy band to control the energy band of the quantum well, so as to weaken the energy band in the quantum well. This method effectively increases the optical power of the LED and the outside Quantum efficiency.Electroluminescence spectroscopy showed that the external quantum efficiency of the LED with bandgap quantum well increased by 10.6% and the luminous power by 9.8% when the injection current was 35 A / cm2. The band simulation shows that the energy band tilt in the quantum well after energy band regulation is weakened and the hole concentration is obviously increased. Therefore, the overlap area of the electron-hole wave function in space is effectively increased, and finally the radiation recombination efficiency is improved.