Nanostructured layer enhancing light extraction from GaN-based scintillator using MOVPE

Abstract

Light extraction (LE) efficiency of GaN buffer layer was studied by angle-resolved photoluminescence. We measured enhancement of light extraction efficiency (LEE) up to 154% by introducing the SiNx layer atop the GaN buffer and subsequent GaN light extraction layer (LEL) overgrowth. Morphological properties of GaN "islands" forming the LEL, such as size and density, have been tuned by various growth parameters. Subsequently, the influence of different growth parameters, such as coalescence time, time of SiNx growth or type of nucleation carrier gas (H2 or N2), on LE was discussed. We also experimentally showed that LE of this layer is more efficient for higher extraction angles. Finally, we present the change in the GaN surface morphology by Si etching in H2 atmosphere during SiNx growth (measured by the atomic force microscopy).