An investigation was made of Mn centres in specimens with initial P and B doping concentrations of 1.5 x 1015 and 6 x 1015/cm3, respectively. All of the known Mn centres were observed, but the Mni3Mni cluster was missing from highly B-doped material. This indicated that the latter center was negatively charged. A new center with trigonal symmetry was observed for an initial B-doping content of 6 x 1015/cm3, and was identified as being a Mni32+ cluster. The electron paramagnetic resonance signal of this center was strongly light-sensitive; unlike the other known Mn clusters.

EPR Investigation of Manganese Clusters in Silicon J.Martin, J.Wedekind, H.Vollmer, R.Labusch: Physical Review B, 2000, 61[3], 1918-23