Density functional theory modelling of amorphous silicon

A first-principles molecular dynamics study of amorphous silicon is reported. The simulated amorphous silicon networks have structural parameters which are generally in better agreement with experimental results than previous numerical studies. In particular, the average first coordination result of 3.96 for the annealed structure is closer to the experimental result of 3.90 than previously reported simulations. This is significant because all previous simulations predicted values greater than 4, implying that five coordinate atoms predominate over three coordinate atoms in a-Si, contrary to the experimental evidence. Further, the average simulated nearest-neighbour distance of (4.46 +/- 0.14) atomic units for the annealed structure is identical to the experimental value. (C) 2000 Elsevier Science B.V. All rights reserved.