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Title: Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films

Abstract

Er-containing silicon compatible materials have been widely used as infrared emitters for microphotonics application. In this field, the additional introduction of a proper sensitizer permits to increase the Er excitation cross sections, thus increasing its optical efficiency. This work aims to investigate the influence of a post-transition metal, bismuth, on the optical properties of erbium-yttrium disilicate thin films synthesized by magnetron co-sputtering. After thermal treatments at 1000 °C in O{sub 2} or N{sub 2} environment, the presence of small precipitates, about 6 nm in diameter, was evidenced by transmission electron microscopy analyses. The spatially resolved chemical nature of the nanoparticles was discerned in the Si and O rich environments by means of scanning transmission electron microscopy–energy dispersive X-ray and scanning transmission electron microscopy–electron energy loss spectroscopy analyses performed with nanometric resolution. In particular, metallic Bi nanoparticles were stabilized in the N{sub 2} environment, being strongly detrimental for the Er emission. A different scenario was instead observed in O{sub 2}, where the formation of Bi silicate nanoparticles was demonstrated with the support of photoluminescence excitation spectroscopy. In particular, a broad band peaked at 255 nm, correlated to the excitation band of Bi silicate nanoparticles, was identified in Er excitation spectrum. Thus Bi silicate clustersmore » act as sensitizer for Er ions, permitting to improve Er emission up to 250 times with respect to the resonant condition. Moreover, the Er decay time increases in the presence of the Bi silicate nanoparticles that act as cages for Er ions. These last results permit to further increase Er optical efficiency in the infrared range, suggesting (Bi + Er)-Y disilicate as a good candidate for applications in microphotonics.« less

Authors:
 [1];  [2]; ; ;  [1];  [3];  [1];  [2];  [2]
  1. CNR IMM-MATIS, Via S. Sofia 64, 95123 Catania (Italy)
  2. (Italy)
  3. Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy)
Publication Date:
OSTI Identifier:
22594343
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH; CROSS SECTIONS; EFFICIENCY; ENERGY-LOSS SPECTROSCOPY; ERBIUM COMPOUNDS; ERBIUM IONS; EXCITATION; HEAT TREATMENTS; MAGNETRONS; NANOPARTICLES; NANOSTRUCTURES; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; PRECIPITATION; SENSITIZERS; SILICON; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X RADIATION; YTTRIUM SILICATES

Citation Formats

Scarangella, A., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, Amiard, G., Boninelli, S., E-mail: simona.boninelli@ct.infn.it, Miritello, M., Reitano, R., Priolo, F., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, and Scuola Superiore di Catania, Università di Catania, Via Valdisavoia 9, 95123 Catania. Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films. United States: N. p., 2016. Web. doi:10.1063/1.4960644.
Scarangella, A., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, Amiard, G., Boninelli, S., E-mail: simona.boninelli@ct.infn.it, Miritello, M., Reitano, R., Priolo, F., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, & Scuola Superiore di Catania, Università di Catania, Via Valdisavoia 9, 95123 Catania. Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films. United States. doi:10.1063/1.4960644.
Scarangella, A., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, Amiard, G., Boninelli, S., E-mail: simona.boninelli@ct.infn.it, Miritello, M., Reitano, R., Priolo, F., Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania, and Scuola Superiore di Catania, Università di Catania, Via Valdisavoia 9, 95123 Catania. Mon . "Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films". United States. doi:10.1063/1.4960644.
@article{osti_22594343,
title = {Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films},
author = {Scarangella, A. and Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania and Amiard, G. and Boninelli, S., E-mail: simona.boninelli@ct.infn.it and Miritello, M. and Reitano, R. and Priolo, F. and Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania and Scuola Superiore di Catania, Università di Catania, Via Valdisavoia 9, 95123 Catania},
abstractNote = {Er-containing silicon compatible materials have been widely used as infrared emitters for microphotonics application. In this field, the additional introduction of a proper sensitizer permits to increase the Er excitation cross sections, thus increasing its optical efficiency. This work aims to investigate the influence of a post-transition metal, bismuth, on the optical properties of erbium-yttrium disilicate thin films synthesized by magnetron co-sputtering. After thermal treatments at 1000 °C in O{sub 2} or N{sub 2} environment, the presence of small precipitates, about 6 nm in diameter, was evidenced by transmission electron microscopy analyses. The spatially resolved chemical nature of the nanoparticles was discerned in the Si and O rich environments by means of scanning transmission electron microscopy–energy dispersive X-ray and scanning transmission electron microscopy–electron energy loss spectroscopy analyses performed with nanometric resolution. In particular, metallic Bi nanoparticles were stabilized in the N{sub 2} environment, being strongly detrimental for the Er emission. A different scenario was instead observed in O{sub 2}, where the formation of Bi silicate nanoparticles was demonstrated with the support of photoluminescence excitation spectroscopy. In particular, a broad band peaked at 255 nm, correlated to the excitation band of Bi silicate nanoparticles, was identified in Er excitation spectrum. Thus Bi silicate clusters act as sensitizer for Er ions, permitting to improve Er emission up to 250 times with respect to the resonant condition. Moreover, the Er decay time increases in the presence of the Bi silicate nanoparticles that act as cages for Er ions. These last results permit to further increase Er optical efficiency in the infrared range, suggesting (Bi + Er)-Y disilicate as a good candidate for applications in microphotonics.},
doi = {10.1063/1.4960644},
journal = {Applied Physics Letters},
number = 6,
volume = 109,
place = {United States},
year = {Mon Aug 08 00:00:00 EDT 2016},
month = {Mon Aug 08 00:00:00 EDT 2016}
}
  • The influence of bismuth on erbium optical properties at 1.54 μm has been investigated in yttrium-erbium disilicate thin films synthesized by magnetron co-sputtering and implanted with two Bi different doses. The Bi depth distribution and the evolution of its oxidation states after annealing treatments at 1000 °C in two atmospheres, O₂ and N₂, have been investigated. It was found that only in O₂ the Bi³⁺ valence state is prevalent, thanks to the enhanced Bi mobility in the oxidizing ambient, as demonstrated by Rutherford backscattering spectrometry. At lower Bi content, although the formation of Bi⁰ metallic nanoparticles that are deleterious nonmore » radiative channels for Er luminescence, efficient energy transfer from Bi to Er has been obtained only in O₂. It is due to the excitation of ultraviolet broad Bi₃⁺ absorption band and the energy transfer to Er ions. We have evaluated that in this case, Er effective excitation cross section increased by a factor of 5 in respect with the one for direct Er absorption at 488 nm. At higher Bi dose, this mechanism is absent, but an increased Er optical efficiency at 1.54 μm has been observed under resonant excitation. It is due to the contribution of a fraction of Er ions having an increased lifetime. This phenomenon is associated with the formation of Bi agglomerates, induced at higher Bi doses, which well isolate Er from non-radiative quenching centers. The increased decay time assures higher optical efficiency at 1.54 μm.« less
  • Continuing the analysis of epitaxial erbium thin films and Er/Y superlattices, we report the effects of basal-plane strain on the modulated spin structure as determined from bulk magnetization and neutron-diffraction measurements detailed in a previous paper (Phys. Rev. B 43, 3123 (1991)). The phase angle of the {ital c}-axis-modulation spin order is larger than that of bulk Er in even the thickest films and is virtually independent of temperature in the superlattices. The sequence and stability of {ital c}-axis commensurate states in bulk Er are altered in all samples considered. In the superlattices, the {ital c}-axis-modulation net moment state withmore » four spins up followed by three spins down dominates the temperature and field phase diagram. In addition, an additional intermediate spin configuration with a net moment of half the saturation moment develops in the superlattice with the thinnest Er interlayers. A phenomenological calculation of the exchange integral demonstrates that epitaxial strain and lattice clamping can lead to an enhancement of the phase angle. Specifically, additional commensurate phases may arise due to strain-induced variations of the nearest-neighbor and next-nearest-neighbor spin interactions, as shown in the context of the axial-next-nearest-neighbor Ising model.« less
  • Crystalline erbium thin films and Er/Y superlattices with varying Er-layer thicknesses have been grown by molecular-beam epitaxy. The magnetic and structural properties of these samples have been analyzed by x-ray-scattering, bulk-magnetization, and neutron-diffraction techniques. From a comparison of the data for the two systems, the importance of interfacial strain relative to artificial modulation in shaping the magnetic behavior has been determined. Though the basic nature of the erbium magnetic order is not qualitatively altered in either the thin films or superlattices, the conical ferromagnetic phase is suppressed in all of the samples considered. The enhanced critical fields exhibit a systematicmore » dependence on Er-layer thickness. These effects appear to follow directly from the epitaxial basal-plane strain which is measurable in films over 14 000 A thick. This strain, along with a clamping'' of the Er thermal expansion to the Y lattice, leads to a reduction of the magnitude of the magnetoelastic energy that drives the ferromagnetic transition. The dependence of the magnetoelastic energy on the epitaxial strain is described by a model which accounts for the elastic coupling of the erbium lattice to the yttrium.« less