Topographic evolution and scaling study of ZnO (0001) single crystal after low-energy atom beam irradiation

The topographic evaluation of the nano-scale pattern, on ZnO (001) surface, and its scaling properties have been investigated here after low energy atom beam irradiation. Preferential sputtering promotes the formation of Zn-rich zones near the surface that serve as the nucleation centers for the spontaneous nanostructure growth. The rms roughness (σ) however increases with irradiation fluence and displays power law behaviour, σ∼tβ, for ttc, σ is independent of irradiation time but interestingly follows the power law behaviour σ∼Lα, where L is the size of image used in analysis. The morphology of the surfaces has also been investigated using the height-height correlation and power spectral density methods. The observed values of growth (β) and roughness (α) exponents indicate a scaling behavior that is induced by the disordered but well-defined geometry of the nanostructures.