Visualization of Light Elements using Annular Bright Field Imaging with a Cs-corrected Scanning Transmission Electron Microscope

Most functional materials (ceramics, semi-conductor and metallic alloys) contain not only heavier elements but also light elements, such as oxygen, nitrogen and carbon. It is important to know the atomic arrangement of these elements. However, High angle annular dark field (HAADF) images of those materials usually do not produce any contrast from the light element columns, because the contrast in the image is approximately proportional to the square of the atomic number. Annular bright field (ABF) imaging by Scanning transmission electron microscope (STEM) has recently been found as a novel technique to visualize light elements and heavier elements in the same image. The recent theoretical study by Findley et al7,8) reveals that ABF imaging produces robust dark contrast on atomic columns which is non-oscillating: independent of sample thickness and of the focus of its image. This characteristic of the ABF imaging results in easily interpretable images unlike STEM BF imaging. This paper describes experimental details about results of the visualization of light elements for three ceramics (two oxides and one nitride) using an ABF imaging technique.