We find a reduction in TD density in GaN films grown on graded AlxGa1-xN buffer layers, in comparison with those grown directly on a thin AlN buffer layer.

• 与那些直接生长在AlN薄膜上的GaN薄膜相比，生长在组分渐变的AlxGa1-xN 缓冲层上的GaN薄膜内具有更少的螺位错密度。