Abstract
The occurrence of large unit cells on semiconductor surfaces is analysed in a general way on the assumption that the surface atoms, even if nominally identical, are differentiated into two types. This could include the atoms being in two different bonding configurations, or being missing, or being replaced by impurity atoms. The energy of the surface configuration is computed as a sum of two-atom interactions, using a Morse potential. It is found that the energy does not depend strongly on the proportions and arrangements of the surface centres. This leads to the conclusion that quite small features of the surface interactions can be responsible for the observed large surface unit cells. Calculations for Ge and Si show that the stability of the surface structures increases in the order 1 × 1, 2 × 1, 2 × 2 and 2 × 8 (equal), 7 × 7. This is consistent with LEED observations on Ge and Si.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call