A study was made of clean and well-annealed (113) surfaces by using scanning tunnelling microscopic and low-energy electron diffraction techniques. It was found that the surface consisted of very large 3 x 1 reconstructed domains, with many small 3 x 2 antiphase domains scattered among them. The use of scanning tunnelling microscopy revealed that neither the 3 x 1 nor the 3 x 1 reconstruction had a mirror plane. This ruled out all of the proposed (113)Si-derived models for the present surface. A model without a mirror plane was proposed here for the 3 x 1 reconstruction. This model involved a re-bonded atom and an adatom, as well as 5 dangling bonds, in each unit cell. A model was also proposed for the 3 x 2 reconstruction. This was different from, but similar to, an interstitialcy model which had recently been proposed for the Si(113)-3 x 2 surface. The unit cell of the present 3 x 2 model consisted of 2 unit cells of the present 3 x 1 model, and a sub-surface interstitial in one of the 3 x 1 unit cells. Both of the proposed models were consistent with the observed scanning tunnelling microscopic images.

Z.Gai, H.Ji, B.Gao, R.G.Zhao, W.S.Yang: Physical Review B, 1996, 54[12], 8593-9