Direct imaging of a novel silicon surface reconstruction.

Silicon surface reconstructions are directly observed in profile by high-resolution transmission-electron microscopy. Low-energy surface facets are formed at edges by in situ annealing of a 〈110〉 thin specimen at an ambient pressure of ${10}^{\mathrm{\ensuremath{-}}9}$ Torr. As well as 〈111〉, 〈100〉, and 〈110〉 reconstructed surfaces, extensive areas of flat 〈113〉 surface are found. By inspection of high-resolution images from the 〈113〉 surface a model involving one dimer per surface (1\ifmmode\times\else\texttimes\fi{}1) unit cell is proposed, suggesting that low-energy surfaces need not be confined to high-symmetry orientations.