In situ ultra-high vacuum transmission electron microscopy studies of the transient oxidation stage of Cu and Cu alloy thin films

► We study the oxidation of Cu, Cu-Ni and Cu-Au thin films by in situ transmission electron microscopy. ► Heteroepitaxial concepts are synergistic with the initial oxidation stage of Cu, Cu-Ni and Cu-Au. ► The Cabrera Mott model does not describe the passivation behavior of Cu since Cu forms oxide islands. ► Addition of Au or Ni to Cu thin film alters the initial oxidation kinetics and oxide morphologies.