TEM Study of Fractal Scaling in Nanoparticle Agglomerates obtained by Gas-phase condensation

摘要

The morphology of the nanoparticle agglomerates obtained during the gas-phase condensation method has been catalogued as fractal but no attempt has been made to determine their fractal dimension (D'). In the present study, we used transmission electron microscopy (TEM) to investigate the fractal character of such samples by processing two--dimensional TEM images. The area perimeter method gives a fractal dimension of around l.3, and its suitability to distinguish between nanocrystalline samples prepared under different experimental conditions or synthesised by different methods has been also demonstrated. The fractal dimension has been related to band-gap and surface area measurements for some selected examples. The advantages and limitations of the fractal technique applied to these systems are examined and discussed.