Figure S2

XPS spectra of Ru3d core level for a 50-cycle Ru ALD using RCpEt(CO)2 as a precursor. Peak 1 is Ru3d5/2 with a binding energy of 280.1ev. Peak 2 is a Ru3d3/2 peak (split spin-orbit component) with a binding energy of 284.2ev. Peaks 3 and 4, at binding energies of 286.0 and 288.2 eV, are attributed to Carbon contamination on the surface.