Towards an enhanced coupling between the Er ions and Si nanoclusters

Abstract

International audienceThe reactive magnetron co-sputtering of two confocal SiO 2 and Er 2 O 3 cathodes in argon–hydrogen plasma was used to deposit Er-doped Si-rich-SiO 2 layers. The effects of deposition conditions (such as hydrogen rate and substrate temperature) and annealing treatment (temperature and time) on the structural, compositional and photoluminescence (PL) properties of the layers were examined. An enhancement was observed of both Er 3+ PL emission and Er 3+ lifetime at 1.54 mm in comparison with their counterparts for the best samples reported so far. It was shown that a lifetime as high as 9 ms can be reached, with comparable PL intensities for resonant and non-resonant excitation lines. The effective cross-section and the fraction of Er ions coupled to Si clusters are analyzed

Optically active Er3+ ions in SiO2 codoped with Si nanoclusters

“…Sample A was grown at 500°C under argon pressure by the cosputtering of three targets ͑SiO 2 , Er 2 O 3 , and Si͒, 15 while sample B was deposited at 100°C under argon-hydrogen mixture by the cosputtering of pure SiO 2 and Er 2 O 3 targets. 16 These samples are the result of an optimization process until achieving maximum PL signal and total lifetime under 476 nm excitation, which is not resonant with an Er 3+ direct transition. The compositions of the samples were measured x-ray photoelectron spectroscopy and secondary ions mass spectroscopy: 8.5 at.…”

“…% of Si excess and 3.4ϫ 10 20 Er/ cm −3 for sample B. 16 Both layers were annealed at 910°C during 60 min in pure nitrogen flow and have a refractive index of about 1.51 at 1.55 m, while the thicknesses were 1.36 and 1.22 m for samples A and B, respectively. In particular, in sample B it was determined an absolute Er 3+ concentration efficiently coupled to the Si-nc of 3.6ϫ 10 19 cm −3 , i.e., 11% of the total Er content.…”

Silicon nanocluster sensitization of erbium ions under low-energy optical excitation

“…This difference is not related to a change in the absorption cross-section (as we are using the same pump conditions), but to the Er 3þ ions presence. 13,14 As already mentioned previously, Er 3þ ions are introduced in our samples during the deposition phase, 19 minimizing, therefore, the occurrence of erbium related defect states. 23 Hence, we associate the difference in emission dynamics (exciton population) with the energy transfer mechanism present in erbium co-doped sample.…”

“…Detailed description of fabrication details can be found in Ref. 19. The sample details are summarized in Table I.…”

Energy transfer mechanism and Auger effect in Er3+ coupled silicon nanoparticle samples

“…confocal pure SiO 2 and Er 2 O 3 targets. 19 To form nanoparticles, a substochiometric silicon rich silicon oxide ͑SRSO͒ is deposited followed by an annealing treatment to ensure phase separation between silicon and its oxide. In order to perform comparative spectroscopic characterization, the deposition parameters 20 employed to obtain the best sample in terms of photoluminescence ͑PL͒ intensity ͑under nonresonant pumping-476 nm͒ and lifetime of the 4 I 13/2 → 4 I 15/2 Er 3+ transition, have been used to fabricate a set of different samples with and without Er 3+ and with different annealing treatments, ͑Table I͒.…”