Comprehensive study of group III-nitride light emitting diode structures based on sapphire and ScAlMgO4 (0001) substrate for high intensity green emission

Abstract

To mitigate the green gap problems existing in GaN/InGaN/AlGaN system on sapphire substrate, an In0.17Ga0.83N/InxGa1–xN/AlyGa1–yN based LED structure on ScAlMgO4 (0001) substrate has been introduced for green light (525…565 nm) emission. On ScAlMgO4 (0001) substrate, 35% of In composition with 1.6 nm well thickness and only 15% of Al composition with 1.1 nm thick AlGaN as capping layer on top provide the best LED structure. It provides minimum equivalent lattice mismatch (0.01%) with reasonable overall elastic energy value (0.47 J/m2). Most importantly, it provides at least 10% brighter green light emission than that of sapphire based LED structure.