分别在直流偏置和交流偏置下, 对大功率GaN基LED的电学和光学特性进行了研究。结果显示, 通过改变靠近p型层的量子垒(也就是最后一个量子垒)中的In组分可以调控有源区中的载流子分布。有源区内积累的电子会引起负电容效应。而通过降低有源区量子垒的势垒高度, 可以改善LED中载流子传输特性, 并实现载流子复合速率及通信调制带宽20%的提高。这个工作将有助于理解GaN基LED中载流子分布对频率特性的影响, 并为设计适用于可见光通信的大功率高速LED奠定基础。

The electrical and optical properties of GaN-based high power LEDs were investigated under both DC and AC bias. The results show that the carrier distribution of the active region can be modified by changing the indium concentration of the last quantum barrier. The accumulated electrons in the active region can lead to the negative capacitance effect. The improved carrier transport property for LEDs with lower quantum barrier also helps to increase the recombination rate and modulation bandwidth by 20%. This work will help to understand the influence of carrier distribution on the frequency behavior of GaN-based LEDs.