Investigation of Nanocrystals Using Tem Micrographs and Electron Diffraction Technique

The aim of this work is to determine mean diameter of polycrystalline samples using Scherrer equation. These represent direct connection between mean diameter and crystal structure and morphology by including the Bragg angle and shape factor. Two samples are investigated, first a nano-sized particles of MgO and second a CVD (Chemical Vacuum Deposition) obtained polycrystalline aluminum film. First, shape factor and mean diameter are evaluates using direct measurement of particle morphology from BF-TEM (Bright Field – Transmission Electron Microscopy) images. The value of mean diameter is determined by assuming a lognormal distribution. Than, mean diameter values are evaluated using Scherrer equation applied to SAED (Selected Area Electron Diffraction) images. We obtain for MgO nano-sized a mean diameter about 48 nm from direct measurement, and 70 nm respectively using Scherrer equation, and for Al film 77 nm, and 70 nm respectively.