Photoexcited carrier diffusion near a Si(111) surface and in the Si bulk

Photocarrier diffusivities of Si have been measured near a surface covered with naturally grown oxide layer and in the bulk using the transient grating technique in reflection and transmission geometries, respectively. Within experimental uncertainty, the surface diffusivity near the surface is found to be essentially the same as that in the bulk, indicating that in the medium-high carrier density regime there is no significant surface effects such as surface recombination, surface state trapping or band bending, affecting band edge carrier diffusion.