*2.4. Scanning Electron Microscopy and Elemental Mapping*

The surface microstructure and the elemental mapping of the chemical composition of the 150 nm stainless steel film coated on the copper substrates at fixed deposition rates (i.e., from 0.05 Å/s to 1.45 Å/s); and the evaporated source before and after 150 nm film deposition at a 0.05 Å/s were studied using a JEOL JSM-6010LA InTouchScopeTM scanning electron microscopy (SEM, Tokyo, Japan) device that is equipped with an integrated energy dispersive x-ray spectroscopy (EDS) analyser and operates via the InTouchScope 1.12 software. All SEM images were recorded by the secondary electron mode from the surface region of the samples and then recorded at different magnifications. Elemental distribution and percentages were obtained by the EDS analyser at a process real time of 100 s. Both SEM and EDS analysis were conducted at a working distance of 10 mm and an accelerating voltage of 20 kV, to reduce any possible damage to the tested samples. It is important to note that elements such as carbon, oxygen, and copper were excluded from the EDS elemental composition due to the presence of carbon in the adhesive tape used for mounting the samples into the device, traces of oxygen can remain in the chamber even at a high vacuum condition while copper was the tested substrate beneath the thin film, this being our area of interest.
