Scanning electron microscopy (SEM) was performed on a Zeiss Supra 40 instrument and samples were treated with a 3 to 6 nm thickness gold coating before measurement to prevent charging during imaging. Lamella cross sections of the films were prepared using a FEI DualBeam Helios NanoLab 600i Focused Ion Beam instrument. High resolution transmission electron microscopy (HR-TEM) was performed using a Jeol 2100 transmission electron microscope; 200 kV; double tilt holder. Note that normally ~10% error should be accounted for when calculating distances from TEM data due to the electron optics of the instrumentation. Composition analysis was conducted using high-resolution scanning transmission electron microscopy (STEM) and energy dispersive x-ray spectroscopy (EDX) equipped with an X-Max 80 detector and AZTecanalysis software (Oxford Instruments, Abingdon, UK).