Photoluminescence enhancement of silicon nanocrystals placed in the near field of a silicon nanowire

Abstract

Semiconductor nanowires have an excellent ability to trap, guide, scatter, or absorb light for specific morphology-dependent resonant optical modes. The electromagnetic field enhancement associated with these modes could be used to modify the luminescence of emitters positioned in the vicinity of the nanowire, in a way similar to plasmonic nanostructures. We show that the photoluminescence of a single plane of silicon nanocrystals in silica, positioned at about 3 nm below the surface, can be enhanced by a factor of 2 to 3 in the presence of a silicon nanowire antenna on the silica surface. This could be the basis of a promising fully complementary metal oxide semiconductor compatible process to improve silicon-based light emitting devices, despite a lower enhancement compared to plasmonic nanostructures. Two-dimensional photoluminescence maps recorded for different polarization configurations (incident electric field parallel or perpendicular to the nanowire axis) exhibit different behaviors and can be related to the electric field intensity distribution in the near-field region of the nanowire, where the active silicon nanocrystal layer is located.