Figure 3

XRD reciprocal lattice space map of a-plane In_xGa_1−xN/GaN heterostructure grown on r-plane sapphire. (a) (11\(\bar{2}\)2) map of sample A, (b) (20\(\bar{2}\)0) map of sample A, (c) (11\(\bar{2}\)2) map of sample B, (d) (20\(\bar{2}\)0) map of sample B, (e) (11\(\bar{2}\)2) map of sample C, (f) (20\(\bar{2}\)0) map of sample C.