Figure 1

Atom probe mass spectra averaged over the volume corresponding to the as-deposited Cu₂O:Mg film. The ions collected from the Si substrate are not shown for clarity: (a) full mass spectrum with the relevant atomic and molecular ion species highlighted; (b–d) show selected regions of the spectrum shown in (a), in which the location and abundance of the peaks originating from Mg^nx ions and MgO_x^nx ions shown by green and purple bars, respectively.