Fractal assessment of ZnO thin films using Higuchi’s algorithm

Higuchi fractal assessment of surface microstructures for sol-gel spin coated ZnO thin films have been studied by varying precursor molarities. The conventional root mean square surface roughness measurement provides only vertical roughness. But it doesn’t offer any spatial information. Therefore, change in spatial features of surface morphology is quantified in terms of fractal dimension and Hurst exponent. Fractal dimension decreases and Hurst exponent increases due to increase in precursor molarity. Consequently, spatial roughness of ZnO films increases. It has been observed that larger grain sizes attribute to higher values of Hurst exponent. Higuchi fractal analysis of thin film surfaces might be useful in correlating spatial features of surface with various material properties. Surface tailored ZnO thin films can be used to engineer wettability and sensing properties.