Tailoring spintronic—optoelectronic functionality in MnSO4 doped ZnTe nanocomposites via lattice strain, defect engineering, and room temperature magnetic ordering

In this study, MnSO4 doped ZnTe nanocomposites were synthesized via a polyethylene glycol (PEG) assisted thermal process (190 °C, 9 h), and structural, morphological, optical, and magnetic properties were systematically studied to establish correlations between structure and property. By analyzing Williamson-Hall data via X-ray diffraction (XRD), we confirmed that the Mn2+ had been successfully incorporated into the ZnTe lattice, indicating peak shifts, new reflections (211), (103) and strains within the lattice. Raman spectroscopy revealed phonon softening shift from 177 cm−1 to 170—175 cm−1, asymmetric broadening, and Mn-Te vibrational modes at 250 cm−1, indicating Mn2+ induced lattice distortion. Polycrystalline particles were observed with enhanced surface roughness and porosity when scanned with scanning electron microscopes (SEM’s), and their crystallinity was confirmed with selected-area electron diffraction (SAED’s). TEM observations revealed that MnSO4 particles dispersed on the ZnTe support were non-uniform and relatively large, indicating significant particle aggregation. As shown in PL spectroscopy, defects 440 nm—536 nm are generated by Mn2+ intra-d-transitions and defects caused by doping, for example, Zn vacancies have been observed. Interestingly, vibration sample magnetometer measurements demonstrated distinct hysteresis loops 300 K at room temperature, highlighting the potential for spintronics applications. In this work, we demonstrate that MnSO4 doped ZnTe can serve as both an optoelectronic device and a magnetic device with tunable magnetic and optical properties.