Electroluminescence peaking at 1.3 \mum is observed from high concentration boron-diffused silicon p -n junctions. This emission is efficient at low temperature with a quantum efficiency 40 times higher than that of the band-to-band emission around 1.1 \mum, but disappears at room temperature. The 1.3-\mum band possibly originates from the dislocation networks lying near the junction region, which are introduced by high concentration boron diffusion.