Photoemission study of the reactivity of barium towards SiOx thermal films

► Barium deposited on thermal silicon oxide layer leads to interfacial reaction. ► Ba growth begins according to a layer-by-layer growth mode due to interfacial reaction. ► Reaction forms an interfacial silicate layer, a 2nd layer mainly composed of BaO while the rest of barium is metallic. ► Deposit annealing at mild temperature leads to silicate layers by consumption of silicon oxide. ► Subsequent annealing at 975 K can induce decomposition of barium silicate.