Unveiling Semiconductor Nanostructured Based Holmium-Doped ZnO: Structural, Luminescent and Room Temperature Ferromagnetic Properties

Abstract

This research work describes the synthesis of ZnO nanostructures doped with Ho3+ ions using a conventional sol–gel synthesis method. The nanostructured produced exhibited a wurtzite hexagonal structure in both ZnO and ZnO:Ho3+ (0.25, 0.5, 0.75 mol%) samples. The change in morphology with addition of Ho3+ dopants was observed, which was assigned to Ostwald ripening effect occurring during the nanoparticles’ growth. The photoluminescence emission properties of the doped samples revealed that Ho3+ was emitting through its electronic transitions. Moreover, reduced surface defects were observed in the Holmium doped samples whose analysis was undertaken using an X-ray Photoelectron Spectroscopy (XPS) technique. Finally, enhanced room temperature ferromagnetism (RT-FM) for Ho3+-doped ZnO (0.5 mol%) samples with a peak-to-peak line width of 452 G was detected and found to be highly correlated to the UV–VIS transmittance results.

Encapsulation of ZnO and Ho:ZnO Nanoparticles in the Core of Wrinkled Mesoporous Silica

“…Goel et al reported 5% doping of holmium in ZnO with micron-sized particles . Kabongo et al reported only a 0.75% molar ratio of holmium in ZnO . Ayon et al used the sol–gel method to synthesize holmium-doped ZnO nanorods with a maximum 5% molar ratio of holmium doping .…”

“…33 Kabongo et al reported only a 0.75% molar ratio of holmium in ZnO. 31 Ayon et al used the sol−gel method to synthesize holmium-doped ZnO nanorods with a maximum 5% molar ratio of holmium doping. 32 In the present study, uniform holmium-doped ZnO nanoparticles were successfully synthesized without the use of stabilizers, achieving a 7.5% molar ratio of holmium doping in ZnO.…”

“…There are a limited number of reports of holmium-doped ZnO nanoparticles. − Khataee et al synthesized holmium-doped ZnO nanoparticles that were 40–100 nm in diameter with a maximum 6% molar ratio of holmium . Goel et al reported 5% doping of holmium in ZnO with micron-sized particles .…”

Functional Nanomaterials for Optoelectronics and Photocatalysis

“…The compilation is clearly divided into three categories: (i) optoelectronics, (ii) photovoltaics and (iii) photocatalysis. In the optoelectronics section, the publication of Kabongo et al describes the synthesis of ZnO doped with Ho, exhibiting ferromagnetic properties under microwave excitation [1]. The second publication, by Rauwel et al, reports on the combination of ZnO nanoparticles with CNT and Ag nanoparticles, and emphasizes the plasmonic effect of Ag nanoparticles in the enhancement of UV emission owing to the Burstein-Moss effect [2].…”