Back-to-Basics tutorial: X-ray diffraction of thin films

X-ray diffraction (XRD) is an indispensable tool for characterising thin films of electroceramic materials. For the beginner, however, it can be a daunting technique at first due to the number of operation modes and measurements types, as well as the interpretation of the resultant patterns and scans. In this tutorial article, we provide a foundation for the thin-film engineer/scientist conducting their first measurements using XRD. We give a brief introduction of the principle of diffraction and description of the instrument, detailing the relevant operation modes. Next, we introduce five types of measurements essential for thin film characterisation: 2 theta/omega scans, grazing-incidence scans, rocking curves, pole figures, and azimuth scans (or phi scans). Practical guidelines for selecting the appropriate optics, mounting and aligning the sample, and selecting scan conditions are given. Finally, we discuss some of the basics of data analysis, and give recommendations on the presentation of data. The aim of this article is to ultimately lower the barrier for researchers to perform meaningful XRD analysis, and, building on this foundation, find the existing literature more accessible, enabling more advanced XRD investigations.