Nanocomposites and nanomaterials
Some features of Mn2+ in cubic nanoZnS 
I.P. Vorona1, S.S. Ishchenko1, V.G. Grachev2, N.P. Baran1, S.M. Okulov1,  V.V. Nosenko1, A.V. Selishchev3
1V. Lashkaryov Institute of Semiconductor Physics of the NAS of Ukraine. Prospect Nauky, 45, Kyiv-03028, Ukraine.
E-mail: vvnosenko@ukr.net
2 Physics Department, Montana State University, Bozeman, Montana, 59717 USA.
3 Chemnitz University of Technology, St. der Nationen 62, 09111 Chemnitz, Germany.

Properties of nanoscale materials (ZnS nanoparticles) significantly change when they are activated by various impurities. The detailed study of the structure of impurity centers, including local distortions of the crystal lattice around them, can elucidate the causes of such an influence.
In the present study four manganese-containing nanoZnS powders of different sizes and synthesized by different technological routes were studied using EPR technique to analyze the structure of Mn2+-related centers in detail. All samples demonstrated EPR signal that is not typical for ZnS powders with larger particles (with the sizes in the micrometers range). Computer simulation showed that EPR spectra of all samples can be fitted by two components. The first component with g = 2.0022 ± 0.0002, A = (-63.5 ± 0.5)10-4cm-1, b40  3.510-4cm-1 was assigned to Mn2+ ion in cubic surrounding (Mn(C)). The second component was found to have following parameters g = 2.0022± 0.0002, A = (-63.5± 0.5) 10‑4 cm‑1, b20 = (-36±1)10‑4 cm‑1; it was attributed to Mn2+ ion associated with a planar lattice defect (stacking fault) - Mn2+(D). The ratio of centers amounts Mn2+(C)/Mn2+(D) for the samples studied was 2.1/1 (samples 1,4) and 1.7/1 (samples 2,3), respectively. EPR of Mn2+ ion was shown to be an effective method for detecting planar lattice defects in ZnS nanoparticles.