An optical sensor includes a light-emitter device formed in a body of solid-state material with wide band gap having a surface. The light-emitter device includes a cathode region having a first conductivity type and an anode region having a second conductivity type. The anode region extends into the cathode region from the surface of the body. The anode region and the cathode region define a junction, and the cathode region has, near the junction, a peak defectiveness area accommodating vacancies in the crystalline structure due to non-bound ions or atoms of Group IV or VIII of the periodic table, which may include carbon, silicon, helium, argon, or neon. The vacancies are at a higher concentration with respect to mean values of vacancies in the anode region and in the cathode region. For example, the vacancies in the peak defectiveness area have a concentration of at least 1013 atoms/cm−3.