Degradation Mechanism of Crystalline Quality and Luminescence in In0.42Ga0.58N/GaN Double Heterostructures with Porous InGaN Layer

摘要

In0.42Ga0.58N/GaN double heterostructures on c-plane sapphire substrate were grown livmetal organic chemical vapor deposition. High-angle annular dark field scanning transmission electron microscopy revealed that the In0.42Ga038N layer features a porous structure consisting of multifaceted voids with a density of 10(9) cm(-2) and an average diameter of 74.6 nm, which was attributed to thermodynamically preferential vacancies aggregation. Both photoluminescence and cathodoluminescence showed luminescenCe quenching in the In0.42Ga0.58N layer. A void model invcilVing void surface trapping and hindered radiatiVe recombination quantitatively described the luminescence quenching mechanism Moreover, it is found that the indium (In) precipitates within the In0.42Ga0.58N layer were void-In complexes in nature, consisting ofthe same quenching centers as voids and adversely affecting the luminescence. These results will provide critical insight into the optical' degradation of InGaN-based light-emitting devices with high In content.