Figure 3

Cross-sectional TEM images of GaN grown on PSS with (a) 25-nm-thick GaN NL, (d) 25-nm-thick AlGaN NL, and (g) 25-nm-thick sputtered AlN NL. 1st Row: The magnified TEM images of GaN NL on (b) flat c-plane sapphire and (c) inclined sidewall of PSS. 2nd Row: The magnified TEM images of AlGaN NL on (e) flat c-plane sapphire and (f) inclined sidewall of PSS. 3rd Row: The magnified TEM images of sputtered AlN NL on (h) flat c-plane sapphire and (i) inclined sidewall of PSS.