Characterization of Si(112) and In/Si(112) studied by SPA-LEED

High index surfaces are of strong interest in todays research because of the possibility to grow low dimensional structures. It has for instance already been shown that the adsorption of Ga can induce the formation of 1D metal chains on Si(112) (cf. Snijders et al., PRB 72, 2005). In this work we investigated the clean Si(112) surface and the adsorption of In on Si(112) to establish an analogy to Ga/Si(112) using spot profile analyzing low energy electron diffraction (SPA-LEED). By means of reciprocal space mapping we determined the bare Si(112) surface to be decomposed into alternating (5512) and (111) facets in [1 anti 10] direction with (2 x 1) and (7 x 7) reconstruction, respectively (cf. Baski et al., Surf. Sci. 392, 1997). With SPA-LEED we were able to observe the decreasing intensity of the facet spots in-situ while depositing In on Si(112) and thus reveal the smoothening of the surface due to the deposition of In. At saturation coverage we found a (3.x1) reconstruction, where x is dependent on the deposition temperature and changes from x=7 at 400 C to x=5 at 500 C. This leads us to the assumption that the reconstruction is not incommensurate but a mixture of (3 x 1) and (4 x 1) building blocks, which is very similar to the super structure of Ga on Si(112).