In this work, CdS nanocrystals (NCs) doped with Mn were synthesized in a glass matrix by fusion. The as-grown Cd1−xMnxS NCs were investigated by optical absorption, atomic force microscopy, and electron paramagnetic resonance (EPR). The incorporation of Mn2+ ions in CdS NCs was confirmed by an absorption transition blueshift with increasing Mn concentration x. EPR spectra demonstrated the existence of two distinct Mn2+ ion locations: one incorporated in the core and the other near the surface of the Cd1−xMnxS NCs. The hyperfine interaction constants used to simulate the EPR spectra were A=7.6 and 8.2 mT, respectively. The synthesis of high quality Cd1−xMnxS NCs may allow the control of optical and magnetic properties.

In this study the fusion method was used to synthesize PbS nanocrystal quantum dots (QDs) embedded in S-doped glass matrix (SiO2−Na2CO3−ZnO−Al2O3−PbO2−B2O3). Optical absorption, atomic force microscopy (AFM), and photoluminescence (PL) were used to investigate different samples. Experimental data indicate that the PbS QD-size is controlled by the different annealing times the S-doped glass matrix is submitted to. The size-dependence of the optical transitions in PbS QDs were obtained by numerical calculation and compared with the experimental data. A strong anti-Stokes photoluminescence (ASPL), from green (2.409 eV) to violet (2.978 eV), was found in all samples, at room temperature. A possible microscopic mechanism leading to the ASPL, which involves a two-photon absorption in two separate steps through a surface state, is proposed.

Mn-doped PbS nanocrystals (NCs) in an oxide glass matrix have been synthesized by the fusion method. Two kinds of Mn2+ sites, located inside and on the surface of NCs, are observed by electron paramagnetic resonance (EPR) spectroscopy in the X band and at room temperature. The proportion of their contribution to the hyperfine structure in the EPR spectrum depends strongly on thermal annealing time. The authors illustrate how thermal annealing process manifests itself in engineering the magnetic properties of NCs.

Samples of Pb1−xMnxSe nanocrystals were synthesized by fusion method and characterized by optical absorption, atomic force microscopy, x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. Effects of Mn2+ ion incorporation into PbSe nanocrystals are manifested by well resolved optical spectra for different concentrations of Mn. The EPR spectra of as grown and thermal annealed Pb1−xMnxSe samples show that the magnetic properties of these Mn-doped nanocrystals can be tuned by thermal processes using different annealing times.

The synthesis of manganese-doped PbS (Pb1−xMnxS) nanocrystal (NC) dots within a borosilicate glass matrix has been investigated by atomic force microscopy, electron paramagnetic resonance and magnetic measurements. The fusion method was employed in the preparation of the magnetic semiconductor NC dots whereas the measurements performed showed changes in the physical properties of the manganese-doped dots as a result of the Mn2+-incorporation into the hosting PbS crystal structure. Nevertheless, the data indicated that only a small fraction of the nominal Mn-doping was incorporated into the PbS NC dot, in both lower (0.5%) and higher (40%) nominal doping ends. For the lower nominal Mn-doping end (0.5%) we found only about 0.05% actually incorporated into the PbS NC dot whereas about 0.45% appeared dispersed throughout the glass template as isolated paramagnetic centres.