Room-temperature luminescence from Er-implanted semi-insulating polycrystalline silicon

Semi-insulating polycrystalline silicon films with oxygen concentrations in the range 4-27 at. % were deposited by low-pressure chemical vapor deposition of SiH₄ and N₂O onto silicon substrates, annealed at 920 °C, and then implanted with 2X 10¹⁵ 500 keV Er ions/cm². After annealing at temperatures in the range 300-900°C, the samples show intense room-temperature luminescence around 1.54 µm, characteristic of intra-4ƒ emission from Er³⁺, upon excitation using an Ar ion laser. The luminescence intensity increases with increasing oxygen concentration in the film. The luminescence is attributed to Er³⁺ ions in oxygen-rich shells around Si nanograins, excited by a photocarrier-mediated process.