Ion beam techniques are powerful methods to characterize and modify semiconductor materials. This book shows the application of these techniques to the study of wide bangdap semiconductor heterostructures including GaN-based and ZnO-based materials. These materials are the basis of the most promising high electron mobility transistors and high-power optoelectronic devices, but the continuous road towards miniaturization requires accurate techniques to control the epitaxial growth of these crystalline layers. This book explores the advantages and limits of ion beam techniques for the structural and compositional characterization in such nanostructures. The fundamentals and applications of Rutherford backscattering spectrometry under channelling conditions are extensively discussed throughout several heterostructures as an alternative and complement to X-ray diffraction methods.