A Fractal Analysis of the Nucleation Transition in Annealed La2O3 Thin Films

Abstract

A La2O3 thin film of 57 nm thickness was deposited by the electron beam evaporation method. To investigate the effect of annealing temperature on crystalline structure of La2O3 thin film, surface morphologies and crystalline states of annealed La2O3 thin films were characterized. It was found that fractal patterns presented on the surfaces of crystallized films with cubic phase. The connections between the annealing temperature and the surface morphology were disclosed by fractal analysis. Fractal dimension and multifractal spectra were calculated. It showed that the annealing temperature apparently affected the width of spectrum $$ \Delta a $$ and the range of probability $$ \Delta f $$ . Combining fractal characteristics with x-ray diffraction (XRD) results, it was found that there was a critical annealing temperature in the range of 850–900°C, above which a transition happened from the dominant hexagonal phase nucleation to the prevailing cubic phase nucleation.