... animportant transfer of the oscillator strength to the low-energyside. Moreover, in the emission spectrum, the rich structure of states characterized, in the low-energy side, by the presence of excitons ... that a lowering of the impurity concentration results in a gain of the stability for the nanowire. The impurity concentration plays a role also re-garding the electronic properties. From Fig. ... showing the possibility of an impurity-based engineering of the optical properties of Si-nc. Here, we report on a comprehen-sive investigation of the structural, electronic and optical proper-ties...