不同构型(In,Al)GaN合金发光机理的第一性原理研究

基于第一性原理的密度泛函理论，研究了纤锌矿（In，Al）GaN合金的4种构型（均匀、短链、小团簇、团簇-链共存模型）的电子结构和发光微观机理。结果表明，在InGaN合金中，短In-N-链和小In-N团簇都局域电子在价带顶（VBM）态。当小团簇与短链共存时，前者局域电子的能力明显强于后者，是辐射复合发光中心。然而，在AlGaN合金中，电子在VBM态的局域受短Al-N链和小Al-N团簇的影响并不显著。合金微观结构的不同会引起电子局域的改变，从而影响材料的发光性能，并对带隙和弯曲系数有重要影响。

First-principles Study of The Light-emitting Mechanism on (In,Al)GaN Alloys with Different Configurations

The electron structures and micromechanism of light emission on wurtzite (In,Al)GaN alloys with four configurations (uniform, short chain, small cluster and a combination of clusters and chains) were investigated based on first-principles density functional theory. The results show that the electrons of both short In-N-chain and small In-N clusters in InGaN alloy are localized at the valence band maximum (VBM) states. When the small cluster and the short chain coexist in the InGaN alloy, the former is much stronger than the latter in terms of the ability of electrons localization, and the small cluster is the radiative recombination luminescence center. However, in AlGaN alloy, the effect of the short Al-N-chain and the small Al-N clusters on the valence electrons localization at the VBM states is not remarkable. Microstructure difference of alloy can cause the change of the electronic localization, which affects the luminescence performance of the material, and the difference also has significant influence on the band gap and the bowing parameter.