Wetting and interfacial chemistry of metallic films on the hydroxylated α − Al 2 O 3 ( 0001 ) surface

摘要: The wetting and the interfacial chemistry of titanium, aluminium, silver films on hydroxylated$\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}(0001)$ surface have been studied in situ during growth films. was probed by differential reflectance photoemission. On bare $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}(0001)$, examination O $1s$ level shows that $(1\ifmmode\times\else\texttimes\fi{}1)$-unreconstructed cannot be completely dehydroxylated, even annealing vacuum, fingerprint remaining OH $(3\ifmmode\pm\else\textpm\fi{}1.5\ifmmode\times\else\texttimes\fi{}{10}^{14}\phantom{\rule{0.3em}{0ex}}\mathrm{O}\mathrm{H}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2})$ being a high binding energy shift. first atomic layer either titanium or aluminium reacts with to produce an oxidized thickness. metallic then grow 3D mode this intermediate layer, so cleavage is expected occur at $\mathrm{Me}\ensuremath{-}\mathrm{Me}∕\mathrm{Me}\ensuremath{-}\mathrm{O}\ensuremath{-}\mathrm{Al}$ interface $(\mathrm{Me}=\mathrm{Al},\mathrm{Ti})$. Therefore, hydroxylation does not appear as panacea promote perfect for metals alumina. $\mathrm{Ag}∕\mathrm{Ti}∕\text{alumina}$ assembly has also examined. Contrasted behaviors are observed depending whether oxide $(0.2\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ form $(g0.2\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$. In former case, little difference respect alumina, while wets almost perfectly alumina covered titanium.