Influence of GaN template thickness and morphology on AlxGa1−xN luminescence properties

► AlxGa1−xN was grown on different GaN templates. ► Better luminescence property is obtained with 1.3 μm-thick GaN template. ► Alloy disorder induces PL peak linewidth increase. ► A bowing parameter of 0.93 eV is obtained. ► Two quenching mechanisms of the donor bound exciton PL-intensity are discussed.