Grain nucleation and growth on amorphous silicon.

摘要

Surface diffusion on amorphous silicon was investigated via both simulations and experiments. Molecular dynamics simulations yielded diffusion Arrhenius parameters close to published experimental values. Diffusion occurs by short migration of atoms following the breaking of strained four-membered rings, in contrast to the long-lived adatoms that mediate diffusion on a crystalline surface. Experiments found that the gas-phase seeding of hemispherical crystalline grains on the amorphous silicon surface has high activation energies for both nucleation and grain growth. The effect of non-thermal illumination upon grain growth during annealing was also studied. However, a full investigation was not possible due to the limitations of the vacuum chamber conditions and also the fragility of many of our amorphous silicon films.