Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination

Manica, Marina; Suchea, Mirela Petruta; Manica, Dumitru; Pascariu, Petronela; Brincoveanu, Oana; Romanitan, Cosmin; Pachiu, Cristina; Dinescu, Adrian; Muller, Raluca; Antohe, Stefan; Manoli, Daniel Marcel; Koudoumas, Emmanuel

doi:10.3390/nano15171369

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Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination

by

Marina Manica

^1,2,

Mirela Petruta Suchea

^1,3,*

,

Dumitru Manica

¹

,

Petronela Pascariu

^1,4,*,

Oana Brincoveanu

¹,

Cosmin Romanitan

¹

,

Cristina Pachiu

¹

,

Adrian Dinescu

¹,

Raluca Muller

¹

,

Stefan Antohe

^2,5,*

,

Daniel Marcel Manoli

^6,*

and

Emmanuel Koudoumas

^1,3,*

¹

National Institute for Research and Development in Microtechnologies—IMT Bucharest, 126A, Erou Iancu Nicolae Street, 077190 Bucharest, Romania

²

R&D Center for Materials and Electronic & Optoelectronic Devices (MDEO), Faculty of Physics, University of Bucharest, Atomiștilor Street 405, 077125 Măgurele, Ilfov, Romania

³

Center of Materials Technology and Photonics (CEMATEP), School of Engineering and Research and Innovation Center (PEK), Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, Greece

⁴

Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania

⁵

Academy of Romanian Scientists (AOSR), Ilfov Street 3, 050045 Bucharest, Romania

⁶

Soil Mechanics and Foundation Engineering, Technical University of Civil Engineering Bucharest, 020396 Bucharest, Romania

^*

Authors to whom correspondence should be addressed.

Nanomaterials 2025, 15(17), 1369; https://doi.org/10.3390/nano15171369

Submission received: 17 July 2025 / Revised: 29 August 2025 / Accepted: 29 August 2025 / Published: 4 September 2025

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Abstract

In this study, we report the fabrication and multi-technique characterization of pure and rare-earth (RE)-doped ZnO thin films using nanostructured microclusters synthesized via electrospinning followed by calcination. Lanthanum (La), erbium (Er), and samarium (Sm) were each incorporated at five concentrations (0.1–5 at.%) into ZnO, and the resulting powders were drop-cast as thin films on glass substrates. This approach enables the transfer of pre-engineered nanoscale morphologies into the final thin-film architecture. The morphological analysis by scanning electron microscopy (SEM) revealed a predominance of spherical nanoparticles and nanorods, with distinct variations in size and aspect ratio depending on dopant type and concentration. X-ray diffraction (XRD) and Rietveld analysis confirmed the wurtzite ZnO structure with increasing evidence of secondary phase formation at high dopant levels (e.g., Er₂O₃, Sm₂O₃, and La(OH)₃). Raman spectroscopy showed peak shifts, broadening, and defect-related vibrational modes induced by RE incorporation, in agreement with the lattice strain and crystallinity variations observed in XRD. Elemental mapping (EDX) confirmed uniform dopant distribution. Optical transmittance exceeded 70% for all films, with Tauc analysis revealing slight bandgap narrowing (Eg = 2.93–2.97 eV) compared to pure ZnO. This study demonstrates that rare-earth doping via electrospun nanocluster precursors is a viable route to engineer ZnO thin films with tunable structural and optical properties. Despite current limitations in film-substrate adhesion, the method offers a promising pathway for future transparent optoelectronic, sensing, or UV detection applications, where further interface engineering could unlock their full potential.

Keywords: ZnO thin films; rare-earth doping; electrospinning–calcination; nanostructured microclusters; La:ZnO; Er:ZnO; Sm:ZnO; bandgap tuning; Raman spectroscopy; transparent optoelectronics

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MDPI and ACS Style

Manica, M.; Suchea, M.P.; Manica, D.; Pascariu, P.; Brincoveanu, O.; Romanitan, C.; Pachiu, C.; Dinescu, A.; Muller, R.; Antohe, S.; et al. Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination. Nanomaterials 2025, 15, 1369. https://doi.org/10.3390/nano15171369

AMA Style

Manica M, Suchea MP, Manica D, Pascariu P, Brincoveanu O, Romanitan C, Pachiu C, Dinescu A, Muller R, Antohe S, et al. Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination. Nanomaterials. 2025; 15(17):1369. https://doi.org/10.3390/nano15171369

Chicago/Turabian Style

Manica, Marina, Mirela Petruta Suchea, Dumitru Manica, Petronela Pascariu, Oana Brincoveanu, Cosmin Romanitan, Cristina Pachiu, Adrian Dinescu, Raluca Muller, Stefan Antohe, and et al. 2025. "Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination" Nanomaterials 15, no. 17: 1369. https://doi.org/10.3390/nano15171369

APA Style

Manica, M., Suchea, M. P., Manica, D., Pascariu, P., Brincoveanu, O., Romanitan, C., Pachiu, C., Dinescu, A., Muller, R., Antohe, S., Manoli, D. M., & Koudoumas, E. (2025). Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination. Nanomaterials, 15(17), 1369. https://doi.org/10.3390/nano15171369

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Morphological and Optical Properties of RE-Doped ZnO Thin Films Fabricated Using Nanostructured Microclusters Grown by Electrospinning–Calcination

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