Synthesis and characterization of Gd-doped SnS2 nanopowders: structural, optical, and magnetic properties

Dilute magnetic semiconductors (DMSs) with tunable ferromagnetism represent promising materials for spintronic device fabrication. This investigation examines pure and Gd-doped SnS₂ nanoparticles (Sn_1-xGd_xS₂, x = 0.00, 0.01, 0.03, 0.05, 0.07) synthesized hydrothermally. Characterization methods included X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–Vis spectroscopy, Raman spectroscopy, photoluminescence, and vibrating sample magnetometry (VSM). XRD analysis confirmed a hexagonal crystal structure, with dopant-dependent crystallite sizes calculated via the Scherrer equation. FESEM revealed nanoparticle dimensions of 100–500 nm. Diffuse reflectance spectroscopy demonstrated progressive increases in both reflectance spectra and band gap energies, indicating a blue shift. Photoluminescence measurements under 259 nm excitation showed visible-region emission peaks, with increasing Gd concentration producing a blue shift in green emission due to band gap expansion. Raman spectroscopy identified an A_1g mode at 312 cm⁻¹, confirming the 2H polytype of SnS₂. CIE chromaticity analysis suggests potential applications in domestic lighting. The weak ferromagnetic behavior observed in Gd-doped samples correlates with tin vacancies (V_Sn), explaining the magnetic properties of the nanoparticles.