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
National Institute for Research and Development in Microtechnologies-IMT Bucharest, 126A, Erou Iancu Nicolae Street, 077190 Voluntari-Bucharest, Romania.
R&D Center for Materials and Electronic & Optoelectronic Devices (MDEO), Faculty of Physics, University of Bucharest, Atomiștilor Street 405, 077125 Măgurele, Ilfov, Romania.
Nanomaterials (Basel). 2025 Sep 4;15(17):1369. doi: 10.3390/nano15171369.
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., ErO, SmO, and La(OH)). 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.
在本研究中，我们报告了使用通过静电纺丝随后煅烧合成的纳米结构微团簇制备纯的和稀土（RE）掺杂的ZnO薄膜及其多技术表征。镧（La）、铒（Er）和钐（Sm）分别以五种浓度（0.1 - 5原子%）掺入ZnO中，所得粉末通过滴铸法制成玻璃基板上的薄膜。这种方法能够将预先设计的纳米级形态转移到最终的薄膜结构中。扫描电子显微镜（SEM）进行的形态分析显示，主要为球形纳米颗粒和纳米棒，其尺寸和纵横比因掺杂剂类型和浓度而有明显变化。X射线衍射（XRD）和Rietveld分析证实了纤锌矿ZnO结构，且在高掺杂水平（例如，ErO、SmO和La(OH)）下有越来越多的二次相形成证据。拉曼光谱显示了由稀土掺入引起的峰位移、展宽和与缺陷相关的振动模式，这与XRD中观察到的晶格应变和结晶度变化一致。元素映射（EDX）证实了掺杂剂的均匀分布。所有薄膜的光学透过率均超过70%，Tauc分析表明与纯ZnO相比带隙略有变窄（Eg = 2.93 - 2.97 eV）。本研究表明，通过静电纺丝纳米团簇前驱体进行稀土掺杂是一种可行的途径，可用于设计具有可调结构和光学性质的ZnO薄膜。尽管目前薄膜与基板的附着力存在局限性，但该方法为未来透明光电子、传感或紫外线检测应用提供了一条有前景的途径，进一步的界面工程可能会释放其全部潜力。
