{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T00:53:43Z","timestamp":1760057623994,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,2,12]],"date-time":"2025-02-12T00:00:00Z","timestamp":1739318400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Foundations"],"abstract":"<jats:p>This study employs advanced structural characterization techniques, including anomalous small-angle X-ray scattering (ASAXS), small-angle X-ray scattering (SAXS), and X-ray photoelectron spectroscopy (XPS), to investigate erbium (Er3+)-doped silica-based glass-ceramic thin films synthesized via the sol\u2013gel method. This research examines the SiO2-TiO2 and SiO2-TiO2-PO2.5 systems, focusing on the formation, dispersion, and structural integration of Er3+-containing nanocrystals within the amorphous matrix under different thermal treatments. Synchrotron radiation tuned to the LIII absorption edge of erbium enabled ASAXS measurements, providing element-specific details about the localization of Er3+ ions. The findings confirm their migration into crystalline phases, such as erbium phosphate (EPO) and erbium titanate (ETO). SAXS and Guinier analysis quantified nanocrystal sizes, revealing trends influenced by their composition and heat treatment. Complementary XPS analysis of the Er 5p core-level states provided detailed information on the chemical and electronic environment of the Er3+ ions, confirming their stabilization within the crystalline structure. Transmission electron microscopy (TEM) highlighted the nanoscale morphology, verifying the aggregation of Er3+ ions into well-defined nanocrystals. The results offer a deeper understanding of their size, distribution, and interaction with the surrounding matrix.<\/jats:p>","DOI":"10.3390\/foundations5010005","type":"journal-article","created":{"date-parts":[[2025,2,12]],"date-time":"2025-02-12T10:25:57Z","timestamp":1739355957000},"page":"5","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Structural Analysis of Erbium-Doped Silica-Based Glass-Ceramics Using Anomalous and Small-Angle X-Ray Scattering"],"prefix":"10.3390","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5935-870X","authenticated-orcid":false,"given":"Helena Cristina","family":"Vasconcelos","sequence":"first","affiliation":[{"name":"Faculty of Science and Technology, University of the Azores, Ponta Delgada, S. Miguel, 9500-321 Azores, Portugal"},{"name":"Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys, UNL), Department of Physics, NOVA School of Science and Technology, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9356-3045","authenticated-orcid":false,"given":"Maria","family":"Meirelles","sequence":"additional","affiliation":[{"name":"Faculty of Science and Technology, University of the Azores, Ponta Delgada, S. Miguel, 9500-321 Azores, Portugal"},{"name":"Research Institute of Marine Sciences, University of the Azores (OKEANOS), Horta, Faial, 9901-862 Azores, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5893-0660","authenticated-orcid":false,"given":"Re\u015fit","family":"\u00d6zmente\u015f","sequence":"additional","affiliation":[{"name":"Vocational School of Health Services, Bitlis Eren University, 13100 Bitlis, T\u00fcrkiye"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0986-9880","authenticated-orcid":false,"given":"Lu\u00eds","family":"Santos","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Qu\u00edmica, Instituto Superior T\u00e9cnico, University of Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1016\/S0022-3093(98)00365-2","article-title":"Active optical properties of Er-containing crystallites in sol\u2013gel derived glass films","volume":"226","author":"Fick","year":"1998","journal-title":"J. Non-Crystalline Solids"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"043102","DOI":"10.1063\/1.3549157","article-title":"Stimulated emission in the red, green, and blue in a nanostructured glass ceramics","volume":"109","author":"Lahoz","year":"2011","journal-title":"J. Appl. Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4315","DOI":"10.1515\/nanoph-2022-0360","article-title":"Four- and five-photon upconversion lasing from rare earth elements under continuous-wave pump and room temperature","volume":"11","author":"Jiang","year":"2022","journal-title":"Nanophotonics"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4255","DOI":"10.1021\/acsaelm.1c00703","article-title":"Recent Progress of Rare Earth Oxides for Sensor, Detector, and Electronic Device Applications: A Review","volume":"3","author":"Hossain","year":"2021","journal-title":"ACS Appl. Electron. Mater."},{"doi-asserted-by":"crossref","unstructured":"Vasconcelos, H.C., and Pinto, A.S. (2017). Fluorescence Properties of Rare-Earth-Doped Sol-Gel Glasses, IntechOpen.","key":"ref_5","DOI":"10.5772\/intechopen.68534"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1007\/s10971-021-05719-3","article-title":"Sol-gel synthesis of TiO2-SiO2 hybrid films with tunable refractive index for broadband antireflective coatings covering the visible range","volume":"107","author":"Zhao","year":"2023","journal-title":"J. Sol-Gel Sci. Technol."},{"doi-asserted-by":"crossref","unstructured":"Almeida, R.M., Morais, P.J., and Vasconcelos, H.C. (1997). Optical loss mechanisms in nanocomposite sol-gel planar waveguides. Sol-Gel Optics IV, SPIE.","key":"ref_7","DOI":"10.1117\/12.284127"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/S1002-0721(12)60228-2","article-title":"Erbium photoluminescence response related to nanoscale heterogeneities in sol-gel silicates","volume":"31","author":"Vasconcelos","year":"2013","journal-title":"J. Rare Earths"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1016\/S0925-3467(01)00007-6","article-title":"Sol\u2013gel thin film deposition and characterization of a new optically active compound: Er2Ti2O7","volume":"16","author":"Langlet","year":"2001","journal-title":"Opt. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"083121","DOI":"10.1063\/1.3657852","article-title":"Complete energy transfer due to rare-earth phase segregation in optical fiber preform glasses","volume":"110","author":"Lahoz","year":"2011","journal-title":"J. Appl. Phys."},{"key":"ref_11","first-page":"55","article-title":"Intermolecular Energy Migration and Fluorescence","volume":"2","author":"Forster","year":"1948","journal-title":"Ann. Phys."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"836","DOI":"10.1063\/1.1699044","article-title":"A Theory of Sensitized Luminescence in Solids","volume":"21","author":"Dexter","year":"1953","journal-title":"J. Chem. Phys."},{"doi-asserted-by":"crossref","unstructured":"Abdullah, A., Benchafia, E.M., Choi, D., and Abedrabbo, S. (2023). Synthesis and Characterization of Erbium-Doped Silica Films Obtained by an Acid\u2013Base-Catalyzed Sol\u2013Gel Process. Nanomaterials, 13.","key":"ref_13","DOI":"10.3390\/nano13091508"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1716","DOI":"10.1364\/OME.9.001716","article-title":"Control of the formation and luminescent properties of polymorphic erbium silicates on silicon","volume":"9","author":"Gao","year":"2019","journal-title":"Opt. Mater. Express"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"11128","DOI":"10.1021\/acs.chemrev.5b00690","article-title":"Small Angle X-ray Scattering for Nanoparticle Research","volume":"116","author":"Li","year":"2016","journal-title":"Chem. Rev."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"5031","DOI":"10.1039\/C9CE02003A","article-title":"Crystallization of BaF2 from droplets of phase separated glass\u2014Evidence of a core-shell structure by ASAXS","volume":"22","author":"Hoell","year":"2020","journal-title":"CrystEngComm"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4018","DOI":"10.1021\/acs.jpclett.1c00557","article-title":"Direct Observation of the Xenon Physisorption Process in Mesopores by Combining In Situ Anomalous Small-Angle X-ray Scattering and X-ray Absorption Spectroscopy","volume":"12","author":"Gericke","year":"2021","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"184207","DOI":"10.1103\/PhysRevB.81.184207","article-title":"Analysis of nanostructure and nanochemistry by ASAXS: Accessing phase composition of oxyfluoride glass ceramics doped with Er3+\/Yb3+","volume":"81","author":"Haas","year":"2010","journal-title":"Phys. Rev. B"},{"unstructured":"Santos, L.F., Barros Marques, M.I., Vasconcelos, H.C., Almeida, R.M., and Lyon, O. (2024, November 12). Caracteriza\u00e7\u00e3o de Filmes Finos por SAXS e ASAXS. F\u00edsica 2000 (Oral Presentation): 12\u00aa Confer\u00eancia nacional de F\u00edsica: 10\u00ba Encontro Ib\u00e9rico Para o Ensino da F\u00edsica, Sociedade Portuguesa de F\u00edsica, 27\u201330 September 2000, Figueira da Foz, Portugal. Abstract. Available online: https:\/\/www.yumpu.com\/pt\/document\/read\/5920105\/programa-nautilus-universidade-de-coimbra.","key":"ref_19"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1045","DOI":"10.1016\/j.trechm.2021.09.005","article-title":"Anomalous small-angle X-ray scattering for materials chemistry","volume":"3","author":"Sun","year":"2021","journal-title":"Trends Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1107\/S1600576713030100","article-title":"ASAXS study of CaF2 nanoparticles embedded in a silicate glass matrix","volume":"47","author":"Hoell","year":"2014","journal-title":"J. Appl. Crystallogr."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6916","DOI":"10.1063\/1.360458","article-title":"Stoichiometry of Cd(S,Se) nanocrystals by anomalous small-angle x-ray scattering","volume":"78","author":"Ramos","year":"1995","journal-title":"J. Appl. Phys."},{"unstructured":"Sazaki, S. (1984). Anomalous Scattering Factors for Synchrotron Radiation Users. Calculated Using Cromer and Liberman\u2019s Method, KEK Report, National Lab. for High Energy Physics (Tsukuba, Japan).","key":"ref_23"},{"unstructured":"(2024, November 10). Skuld. (n.d.). AS Periodic. University of Washington. Retrieved 10 November 2024. Available online: http:\/\/skuld.bmsc.washington.edu\/scatter\/AS_periodic.html.","key":"ref_24"},{"doi-asserted-by":"crossref","unstructured":"Blachnio, M., Derylo-Marczewska, A., Charmas, B., Zienkiewicz-Strzalka, M., Bogatyrov, V., and Galaburda, M. (2020). Activated Carbon from Agricultural Wastes for Adsorption of Organic Pollutants. Molecules, 25.","key":"ref_25","DOI":"10.3390\/molecules25215105"},{"unstructured":"Lesieur, P., Lombardo, D., Beauche, C., Creoff, T., Decamps, J.M., Dubuisson, G., Perilhous, S., Lesieur, G., Keller, M., and Ollivon, M. (2024, November 10). New Features at the LURE-D22 SAXS Beamline. Proceedings of the International School and Symposium on Small Angle Scattering (p. 62). Matrahaza, Hungary: Neutron Physics Department, Research Institute for Solid State Physics and Optics. Hosted by the Hungarian Academy of Sciences. Available online: https:\/\/inis.iaea.org\/collection\/NCLCollectionStore\/_Public\/30\/036\/30036868.pdf.","key":"ref_26"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"948","DOI":"10.1107\/S0021889897003555","article-title":"Small-Angle X-ray Scattering Experiments in Grazing Incidence on Sol\u2013Gel Coatings Containing Nano-Scaled Gold Colloids: A New Technique for Investigating Thin Coatings and Films","volume":"30","author":"Kutsch","year":"1997","journal-title":"J. Appl. Cryst."},{"doi-asserted-by":"crossref","unstructured":"Gon\u00e7alves, M.C., Pereira, J.C., Matos, J.C., and Vasconcelos, H.C. (2018). Photonic Band Gap and Bactericide Performance of Amorphous Sol-Gel Titania: An Alternative to Crystalline TiO2. Molecules, 23.","key":"ref_28","DOI":"10.3390\/molecules23071677"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1007\/s13391-012-2083-1","article-title":"Sintering effects on structure, morphology, and electrical properties of sol-gel synthesized, nano-crystalline erbium oxide","volume":"8","author":"Bakhsh","year":"2012","journal-title":"Electron. Mater. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"065024","DOI":"10.1088\/1402-4896\/ad4785","article-title":"X-ray diffraction for phase identification in Ti-based alloys: Benefits and limitations","volume":"99","author":"Bolzoni","year":"2024","journal-title":"Phys. Scr."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3075","DOI":"10.1039\/D0MA00978D","article-title":"Bright aspects of defects and dark traits of dopants in the photoluminescence of Er2X2O7:Eu3+ (X = Ti and Zr) pyrochlore: An insight using EXAFS, positron annihilation and DFT","volume":"2","author":"Gupta","year":"2021","journal-title":"Mater. Adv."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1010","DOI":"10.1021\/ja01379a006","article-title":"The principles determining the structure of complex ionic crystals","volume":"51","author":"Pauling","year":"1929","journal-title":"J. Am. Chem. Soc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"e4802","DOI":"10.1002\/bio.4802","article-title":"Synthesis, structural, and optical behavior of erbium-doped silicophosphate glasses for photonics applications","volume":"39","author":"Bouabdalli","year":"2024","journal-title":"Luminescence"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"114950","DOI":"10.1016\/j.optmat.2024.114950","article-title":"Spectroscopic characteristics and gain cross-section profiles of erbium-doped boro-tellurite glasses for optical amplifier applications","volume":"148","author":"Kumar","year":"2024","journal-title":"Opt. Mater."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/S0040-6090(00)01040-3","article-title":"Aerosol\u2013gel preparation of optically active layers in the system Er\/SiO2\u2013TiO2","volume":"372","author":"Coutier","year":"2000","journal-title":"Thin Solid Films"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"545","DOI":"10.4028\/www.scientific.net\/MSF.455-456.545","article-title":"Active Nanocrystals in Erbium-Doped Silica-Titania Sol-Gel Films","volume":"455-456","author":"Santos","year":"2004","journal-title":"Mater. Sci. Forum"},{"unstructured":"Steglich, P. (2020). Optical Waveguides Based on Sol-Gel Coatings. Waveguide Technologies in Photonics and Microwave Engineering, IntechOpen.","key":"ref_37"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1007\/BF02436847","article-title":"Influence of solvent concentration on the microstructure of SiO2\u2212TiO2 sol-gel films","volume":"8","author":"Orignac","year":"1997","journal-title":"J. Sol-Gel Sci. Technol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.susc.2015.06.002","article-title":"Multiplet splitting for the XPS of heavy elements: Dependence on oxidation state","volume":"643","author":"Bagus","year":"2016","journal-title":"Surf. Sci."},{"unstructured":"(2024, November 04). X-RAY DATA BOOKLET, Center for X-Ray Optics and Advanced Light Source. Lawrence Berkeley National Laboratory, Available online: https:\/\/xdb.lbl.gov\/.","key":"ref_40"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1557\/PROC-609-A11.1","article-title":"UPS of a-Si:H: What is the energy of the Er 4f states?","volume":"609","author":"Tessler","year":"2000","journal-title":"MRS Proc."}],"container-title":["Foundations"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2673-9321\/5\/1\/5\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T16:32:16Z","timestamp":1760027536000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2673-9321\/5\/1\/5"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,12]]},"references-count":41,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2025,3]]}},"alternative-id":["foundations5010005"],"URL":"https:\/\/doi.org\/10.3390\/foundations5010005","relation":{},"ISSN":["2673-9321"],"issn-type":[{"type":"electronic","value":"2673-9321"}],"subject":[],"published":{"date-parts":[[2025,2,12]]}}}