Room temperature luminescence of Er doped nc-Si/SiO2 superlattices

Amorphous Si/SiO2 superlattices with a 80 nm top oxide are implanted with various erbium doses (1.2×1015–5.2×1016 cm−2). The effect of Si nanocrystals in the vicinity of the Er ions is investigated. We found that the luminescence intensity is increased compared to an a-SiO2 film implanted with the same erbium dose. The Si layers are completely crystallized with an average crystal size of 5.7 nm after annealing at 800°C. Room temperature luminescence is found at 1.54 μm, and the intensity scales with the annealing time. Increasing the implantation dose decreases the room temperature luminescence intensity. Over the whole range of 7–300 K the luminescence quenches below one order of magnitude. Luminescence at 2, 2.55 and 3.0 eV is assigned to interface defects at the nanocrystal surface and to implantation damage in the SiO2.