Formation of ZnO nanodot arrays along the step edges on R-face sapphire by metalorganic chemical vapor deposition

Dot array formation of zinc oxide (ZnO) along the linear single steps was demonstrated on sapphire substrates under near atmosphere pressure by metalorganic chemical vapor deposition (MOCVD). Sapphire substrates of View the MathML source, (0 0 0 1) and View the MathML source planes (A-plane, C-plane and R-plane, respectively) were employed as templates for manufacturing the nanostructures. For highly controlling dot array formation the substrates were prepared by annealing at 1000 °C for 3 h in air after chemical treatment. The step arrays were easily prepared on C-plane and R-plane sapphire. The linearly aligned ZnO nanodot arrays were formed on R-plane sapphire along the step edges over several ten micrometers. The result can be attributed to the smaller number of dangling bonds on R-plane than on A-plane and C-plane, enhancing the surface diffusion length. Sapphire can be a good template for manipulating II–VI semiconductor on it to form nanostructures even at near atmosphere pressure by a conventional MOCVD.