Scanning electron microscope (SEM), for imaging atomic level defects associated with interfaces between different materials comprises iteratively adjusting the impact energy of an electron beam 20 incident on a sample, 12 in a region proximal to the sample being imaged, and assessing a simulated back-scattered electron image 48 for each adjustment until a plane of origin of defects is located. The back scatter may be simulated though electron flight simulation software. The iterative adjustment of the electron energy may be continued until the electron beam energy matches the energy of a defect associated with an interface between materials. The electron energy may be adjusted by applying a bias voltage to the sample. Energy Dispersive X-ray analysis may also be used to identify the composition of the defects. Quantitative analysis may also be undertaken of a total area covered by defects. Energy filtering may be undertaken with respect to the electrons generated form the sample.
