Mechanism of Cu Deposition on theα−Al2O3(0001) Surface

Abstract

The growth mechanism of the Cu= -Al 2 O 3 (0001) interface is studied by first-principles moleculardynamics simulations as a function of the transition-metal coverage ( ) and the temperature of the system. On the anhydrous surface growth of Cu(0) 3D clusters is predicted. On the partially hydroxylated surface, a Cu(I) monolayer, relatively stable upon the temperature rising, is first observed ( < 1=3 ML). Increasing Cu loading leads to Cu I =Cu 0 mixed phases that when heated aggregate into 3D particles increasing the number of Cu(0) atoms, in agreement with the Auger spectra of Kelber et al

Hydroxylated α-Al2O3 (0001) surfaces and metal/α-Al2O3 (0001) interfaces

“…Cu/a-Al 2 O 3 (0 0 0 1): Concerning Cu/a-Al 2 O 3 (0 0 0 1) interfaces, many experimental and theoretical efforts have been devoted to understand the metal-support interaction [35][36][37][38][39][40][41]. In particular, the role of surface OH on Cu growth has been studied extensively.…”

“…Due to the interaction between surface OH groups and metal adatoms [34][35][36][37][38] it is reasonable to assume the layer-like growth of the three metals on the hydroxylated surfaces. The interaction of every metal with surface OH was studied by XPS.…”

“…The interfacial reactions lead, instead of island growth, to the technologically important 2-D film growth and the oxidation of the metal in the initial stage of nucleation. In general, the strong interaction between metal adatoms and surface OH groups significantly changes the interfacial bonding and solid state wetting behavior [32][33][34][35][36][37][38]. Therefore, fully understanding and well controlling of the hydroxylated a-Al 2 O 3 (0 0 0 1) surface can contribute much to the elucidation of the nature of metal/alumina interfaces.…”

“…The different surface terminations and properties deliberately depend on the surface treatment and can be manipulated by the surface preparation process. The different surface properties will significantly affect the formation of metal/alumina interfaces, for example, nucleation and growth of metal overlayers, interfacial bonding, and thus interfacial energy [32][33][34][35][36][37][38][39][40][41][42][43]. Among the different possible surfaces, the hydroxylated a-Al 2 O 3 surface is of special importance.…”

“…Hydroxylated surfaces are expected to exhibit higher reactivity to metals than clean Al-terminated surfaces [27,[32][33][34][35][36][37]. Theoretical work [34,38] predicted that the reactions of Co and Cu with surface OH groups are exothermic. The interfacial reactions lead, instead of island growth, to the technologically important 2-D film growth and the oxidation of the metal in the initial stage of nucleation.…”