GaN基蓝光LED内量子效率的温度droop效应研究

随工作环境温度的升高，GaN基LED的内量子效率显著下降；该现象被称为温度droop效应。温度droop效应对发光效率的影响甚至会超过随电流密度增加而产生的droop效应。如能消除温度droop效应问题，将可大幅提高GaN基LED在正常工作温度下的发光效率，拓展其应用领域。然而，目前很少有文献报道对温度droop效应的研究，对于其背后的深层物理机理还未有清晰的认识。本项目将以本单位自主研发的硅衬底GaN基LED技术为平台，采用理论与实验相结合的方式系统研究各相关物理机制随温度变化时对内量子效率的影响趋势；并使用解释方法与数值方法相结合进行定量分析。从理论中深入理解T-droop效应产生的原因后，给实验以指导；反过来，又用实验对理论进行验证并不断修正理论模型；进而提出解决温度droop效应问题的方案，设计并制造出更高效的GaN基LED芯片。

GaN-based LED suffer from a strong decrease in internal quantum efficiency with increasing temperature, which is called the temperature droop. The temperature droop can be more detrimental than the current-density droop that means the efficiency decrease with increasing operating current. It is very helpful for improving LED efficiency and application to eliminate the temperature droop. Until now, however, the temperature droop has been less focused on, and the causes of the temperature droop is not comprehensive. The project will be based on the technology of GaN-based LED on Si substrate. Mechanisms that are related to internal quantum efficency will be researched, and their variations with temperature will be understood by combinating theory and experiment. The effect of mechanisms on the temperature droop will be quantificationally analysed by the combination of analytical method and numerical method. The causes of the temperature droop will be comprehended from theory models, which can give a guidance to the experiment. Conversely, theory models can be validated and constantly revised by analysing experiment results. The scheme of improving temperature droop will be proposed, and LED chip with high internal quantum efficiency will be designed and fabricated.