Erbium Emission from Nanoengineered Silicon Surface

Abstract

Optically active SiO_<i>x</i> nanowires were grown on silicon by ion-implanting it with metallic impurities and annealed at 1100 °C in an Ar ambient. The implanted metals precipitate on the silicon surface and act as catalysts for nanowire growth. Ion implantation of erbium into silicon and subsequent heating in an argon ambient resulted in selective nucleation and growth of optically active silica nanowires. The bottom-up nanowire growth, mediated by vapor liquid solid mechanism, was also demonstrated for a multimetal (Au:Er) implant combinations in Si. The role of Er as a catalyst and dopant resulted in optically active silica nanowires that exhibited photoluminescence emission at 1.53 μm from an Er³⁺ intra-4f transition. Time resolved photoluminescence (PL) from these nanostructures indicated a luminescence lifetime of 24 ms, larger than that generally observed for Er-doped bulk silica. This increase in luminescence lifetime is attributed to a reduction in the optical density of states of Er in the nanowire samples. Infrared optical emission from erbium-doped silica nanowires on silicon holds a great potential for implementing wavelength controlled optical nanoswitches, photoresponsive devices and sensitive integrated biosensors.