A light-emitter device comprising: a body of solid-state material; and a PN junction in the body, including: a cathode region, having N-type conductivity; an anode region, having P-type conductivity, extending in direct contact with the cathode region and defining a light-emitting surface; and a depletion region around an interface between the anode and the cathode regions. The light-emitting surface has at least one indentation that extends towards the depletion region. The depletion region has a peak defectiveness area, housing irregularities in crystal lattice, in correspondence of said at least one indentation. The defectiveness area, which includes point defects, line defects, bulk defects, etc., is generated as a direct consequence of the formation of the indentation by an indenter or nanoindenter system. In the defectiveness area color centers are generated.