Quantitative analysis of structural inhomogeneity in nanomaterials using transmission electron microscopy

A method for quantifying inhomogeneity of crystal structure at the nanoscale is suggested and experimentally verified. The method is based on digital processing of images obtained by high-resolution transmission electron microscopy. A series of images is acquired and each image is divided into several overlapping sliding windows. Interplanar distances are determined using a fast Fourier transform and the CrysTBox software. A spatial distribution of the estimated distances is obtained considering the size and position of the sliding window within the analysed sample. This approach provides for a picometric precision and accuracy if applied on ideal data. Although this accuracy was verified on experimental data, it can be worsened by errors specific to a particular application and data acquisition technique. The achieved spatial resolution ranges from a few to tens of nanometres. These levels of accuracy, precision and spatial resolution are reached without the need for aberration correction or for a reference lattice parameter, and using samples prepared by focused ion beam milling.