In recent years, surface science has seen significant progress in understanding the structure and reactivity of ultrathin oxides on surfaces. This line of research has a variety of applications, e.g., in catalysis and in the use of oxides as substrates for cluster growth, including templates for self-organized growth of well-ordered arrays of clusters. With the increasing miniaturization in microelectronics, gate oxides of field effect transistors approach the limit of ultrathin oxides. The talk will focus on two topics in the field of ultrathin oxides, (i) surface oxides on the late transition metals [1] and (ii) ultrathin aluminum oxide layers on aluminum alloys [2]. In both cases, it has been shown that ultrathin oxides can have structures different from bulk oxides. In addition to two-dimensional oxides, one-dimensional oxides have been found on vicinal surfaces of transition metals.
For some metals, there are simple rules of thumb for the structure of surface oxides and oxygen-induced reconstructions. It will be also discussed what determines the reactivity of surface oxides and shown that even inert oxides can play a role in catalytic reactions.
[1] E. Lundgren et al., J. Phys. Cond. Matter 18, R481 (2006) and refs. therein.
[2] G. Kresse et al., Science 308, 1440 (2005); M. Schmid et al., Phys. Rev. Lett. 97, 046101 (2006). |