arXiv:0803.4258. 2008. cond-mat.mtrl-sci. Competing interests The authors declare that they have no competing interests. Authors’ contributions AY and DC carried out the sample preparation, participated on its analysis, performed all the Analyses, and wrote the paper. XL and JL helped perform

the XRD and EDS analyses. SL guided the study and participated in the paper correction. All authors read and approved the final manuscript.”
“Background Er-doped silica-based materials have been extensively studied in the field of optical communication technology for their promising applications as active elements in photonic devices [1–4]. Indeed, the sharp luminescence of Er3+ ions at 1.54 μm matches the standard telecommunication wavelength of silica optical fibers and is absorption-free for Si bandgap. However, the Er3+ luminescence efficiency in silica check details is too low to be practical,

and an expensive and bulky laser tuned to an Er3+ absorption band is required for the excitation of the Er3+ luminescence. Consequently, Si nanoclusters (Si NCs) with large excitation Ipatasertib purchase cross-section and broad excitation band are exploited as sensitizers to improve the excitation efficiency of Er3+[5, 6]. Great deals of researches have committed effort to improve the properties of sensitizers (Si NCs) and to enhance the luminescence efficiency of Er3+[7–9]. As for the Si NCs, both experimental and theoretical studies indicate that the microstructures, especially the interfaces

of Si NCs, play an active role in their optoelectronic properties [10–12]. Furthermore, the optical properties of Si NCs would also be affected by the coalescence of Si NCs, which is universal in silicon-rich oxide (SRO) matrix with sufficient Si excess and long-time post-annealing process [13, 14]. However, there still exist incomprehension and uncertainties regarding the influence of microstructures of Si NCs on the Er3+ optical properties despite of the extensive studies on the sensitization process of Si NCs for Er3+. In this letter, we report on the effect of microstructure evolution of Si NCs on the Er-related luminescence in erbium-doped Tryptophan synthase SRO (SROEr) films. We address in a conclusive way that the coalescence of Si NCs in microstructures would reduce the luminescence of Si NCs, which would further quench the luminescence of Er3+. These results GW786034 molecular weight reveal that separated Si NCs are needed to obtain efficient Er3+ luminescence. Methods SRO (SROEr) films were deposited on p-type silicon substrates by the sputtering (co-sputtering) of a pure Si target or Er2O3 and Si targets in the plasma of Ar-diluted 1% O2 atmosphere, where the amount of Si excess and the Er concentration were modulated by varying the r.f. power from 80 to 160 W for Si and from 15 to 20 W for Er2O3, respectively. The samples with Si excesses of 11%, 36%, 58%, and 88%, and Er concentration of about 5×1019 at.