We have investigated the early stages of Si adsorption on the Ag(110) surface at room temperature (RT) by scanning tunnelling microscopy, Auger electron spectrometry, low energy electron diffraction and synchrotron radiation photo-electron spectroscopy. The initial growth produces the formation of narrow Si nanowires (NW's) of identical width, all oriented along the Ag[-110] direction [1].
Upon further growth, we have recently succeeded in fabricating by self-organization a periodic array of massively parallel (along the Ag[-110] direction) one-dimensional (1 D) Si NW's, 1.6 nm in width, with a 2 nm pitch, thus forming a 1D grating at the nanoscale [2].
Typically, for Si growth at 200°C, or growth at RT followed by annealing, the individual NW's markedly elongate and self-assemble to form by lateral compaction a 5x2 periodic array, i.e., a 1D grating from mesoscopic up to macroscopic scales.
Based on a theoretical atomic geometry of the silicon NW's inferred by He [3], we will propose a new structural model in better agreement with our experimental results obtained both on isolated or self-assembled Si NW's. We will further discuss the electronic properties of the individual NW's and of the massively parallel array.
References:
[1] C. Léandri, G. Le Lay, B. Aufray, C. Girardeaux, J. Avila, M.E. Davila, M.C. Asensio,
C.Ottaviani and A. Cricenti, Surface Sci. 574 (2005)
[2] H. Sahaf , L. Masson, B. Aufray, F. Ronci and G. Le Lay , in preparation
[3] Guo-min He, Phys. Rev. B 73 (2006) 035311
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