On the origin of intense luminescence at 0.93 eV from multi-crystalline silicon

Strong luminescence emission at 0.93 eV appears on some specific grain boundaries in multicrystalline silicon. The emission is generated on spots, forming irregular pattern along those grain boundaries. The spots show also strong non-radiative recombination. Fitting the temperature dependence using an Arrhenius plot indicates a level of 120 meV in the silicon band gap involved in that transition. We relate the appearance of the center to a specific dislocation network formed at slightly misoriented local Σ3 grain boundary parts.