Closing the yellow gap with Eu- and Tb-doped GaN: one luminescent host resulting in three colours

Cordula Braun; Liuda Mereacre; Zheng Chen; Adam Slabon

doi:10.1038/s41598-022-06148-0

Closing the yellow gap with Eu- and Tb-doped GaN: one luminescent host resulting in three colours

Sci Rep. 2022 Feb 15;12(1):2503. doi: 10.1038/s41598-022-06148-0.

Authors

Cordula Braun¹, Liuda Mereacre², Zheng Chen³, Adam Slabon⁴

Affiliations

¹ Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany. Cordula.Braun@kit.edu.
² Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
³ Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056, Aachen, Germany.
⁴ Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16 C, 106 91, Stockholm, Sweden.

Abstract

Gallium nitride (GaN) is a key material when it comes to light-emitting diodes (LEDs) and has pushed the LED revolution in lighting and displays. The concept of down-conversion of a GaN-based blue LED offers the possibility to provide efficient generation of monochromatic, high-color purity light resulting in a highly efficient warm-white all-nitride phosphor-converted light emitting diode (pc-LED). Although the down conversion of blue light from InGaN LEDs has become a dominant technique for producing white light, there are still some technical challenges, e.g. the immiscibility of GaN and InN and the lattice mismatch between the substrate and InGaN, that have to be overcome. Here we demonstrate the doping of bulk GaN with europium, terbium and the combination of both resulting in intriguing luminescence properties, pushing the role of GaN:Eu,Tb as a chief component in future light emitting diodes. This colour tuning proves that one luminescence host can provide three colours (red, green and orange) and that even the so called "yellow gap" could be closed with a III-nitride. By using one material for all colours, it will be possible to overcome the technical challenges in building up LED devices, which will open up new capabilities for modern highly efficient phosphors.