Investigation of linear optical properties of Eu/Si co-doped GaN

Résumé fourni par la source

Third-generation semiconductor GaN-based multiple quantum wells (MQWs) have been widely applied in the fields of solid-state lighting and display devices. The ideal all-N-based full-color display scheme, which replaces traditional AlInGaP/GaAs with N-based red light, is highly appealing. Based on first-principles methods, this study constructs a unit heterojunction model within the MQWs composed of Eu/Si co-doped GaN and AlGaN, and investigates the geometric structures, band structures, density of states (DOS), and optical properties of Eu single-doping and Eu/Si co-doping systems. It is found that Eu doping introduces 4f impurity energy levels in the band gap, while Eu/Si co-doping effectively breaks the spin degeneracy and can induce the generation of spin-polarized carriers. The band offset of the co-doping system is optimized, and the 4f orbital electronic states of Eu are more fully activated through the combined effects of lattice coupling, built-in electric field, and orbital hybridization at the heterojunction interface.Co-doping impacts optical properties by making the characteristic transition peaks narrower in the imaginary part of the dielectric function. It also boosts light absorption in the UV-visible range. This study offers a strong theoretical foundation for creating the perfect all-N-based display system.