Investigation of defect-related optical properties in AlxInyGa1−x−yN quaternary alloys with different Al/In ratios

► Structural and defect-related optical properties of AlxInyGa1−x−yN quaternary alloys are studied. ► Two quenching band positions are found and estimated by the method of optical quenching of photoconductivity. ► Photoluminescence peak structure is related to the quenching behavior. ► The quenching phenomena get stronger with the decrease of Al/In ratio.