Adaptive Paramagnetism and Photoluminescence in Nitrogen, Co-doped Mn: CdS Composite Quantum Dots

This research paper delves into the synthesis and characterization of Mn-doped nitrogen -co-doped CdS composite diluted magnetic semiconductor quantum dots (DMSQDs) using a co-precipitation method (CPM) at room temperature. The introduction of nitrogen is strategically employed to improve the structural stability of DMSQDs, capitalizing on it's ability to exist in diverse ionic states. The investigation covers the structural, optical, and magnetic properties of the synthesized quantum dots. X-ray diffraction (XRD) analysis confirms the cubic phase of CdS and unveils the presence of secondary phases, including MnS and S2N4, signifying successful Mn and N incorporation into the CdS lattice. Elemental analysis via energy-dispersive X-ray spectroscopy (EDX) validates the presence of Mn and N in the quantum dots. Optical studies, encompassing Ultraviolet-Visible spectra (UV-Vis) and photoluminescence (PL), reveal a distinctive blue shift in the absorption band edge, highlighting the quantum confinement effect. The PL spectra unveil the presence of manganese ions and showcase a characteristic emission peak at 634 nm. Electron paramagnetic resonance (EPR) analysis establishes the paramagnetic nature of Mn-doped CdS composite quantum dots, with nitrogen influencing the g value. This study offers valuable insights into the potential applications of these DMSQDs in the realm of spintronic devices.