绿光LED有源区中极化自屏蔽效应的研究

On the polarization self-screening effect in the active region of green light-emitting diode

设计了一种具有自屏蔽量子限制斯塔克效应(QCSE)的绿光LED。该器件主要是用沿极性面[0001]方向生长的InN组分渐变量子垒来替代传统的GaN量子垒,从而在量子垒的内部产生极化体电荷。该极化体电荷能够抵消由极化作用在异质结界面处产生的界面电荷,进而有效地屏蔽量子阱内所产生的内建极化电场。另外InN组分的提高,一定程度上降低了量子垒的势垒高度,促进了空穴注入有源区。因此,器件的光输出功率和外量子效率(EQE)均得到显著提升。

This work investigates polarization self-screening effect for the multiple quantum wells of[0001]oriented In⁃GaN/GaN green light-emitting diodes(LEDs).The polarization self-screening multiple quantum wells have the quantum barriers with graded InN composition.Then,the polarization induced bulk charges can be generated in the proposed quantum barriers which can screen the polarization induced interface charges at quantum barrier/quantum well interfac⁃es.Therefore,the polarization induced electric field in the quantum wells can be effectively screened.In addition,the re⁃duced barrier height for the propose multiple quantum wells can simultaneously promote the hole transport in the active region.As a result,both the optical output power density and external quantum efficiency(EQE)for the proposed green LEDs have been significantly improved.