SiOx layers were fabricated by thermal evaporation of SiO powders onto p-type Si(100) substrates at 200 degreesC to investigate the electrical and light-emitting properties of the layers. After deposition, Ni ions of 70 keV were also implanted into SiOx layers at room temperature. Then both of the as-deposited and as-implanted samples were annealed in N-2 ambient for 2 h at 500 degreesC. Violet photoluminescence (PL) due to radiative defects was observed from all the SiOx samples but annealed ones showed more intense PL than unannealed samples. Red electroluminescence (EL) was obtained from the SiOx in metal-insulator-semiconductor (MIS) structures and the annealed SiOx layers also exhibit more intense EL than unannealed layers. Particularly, the SiOx annealed after Ni-implantation showed the most intense EL which may be caused by highly concentrated radiative defects in the implanted SiOx.