Room-temperature electroluminescence at 1.54 µm is demonstrated in erbium-implanted oxygen-doped silicon (27 at. % O), due to intra-4ƒ transitions of the Er3+. The luminescence is electrically stimulated by biasing metal-(Si:O, Er)-p+silicon diodes. The 30 -nm-thick Si:O, Er films are amorphous layer deposited onto silicon substrates by chemical-vapor deposition of SiH4 and N2O, doped by ion implantation with Er to a concentration up to ª 1.5 at. %, and annealed in a rapid thermal annealing furnace. The most intense electroluminescence is obtained in samples annealed at 400 ³C in reverse bias under breakdown conditions and it is attributed to impact excitation of erbium by hot carriers injected from the Si into the Si:O, Er layer. The electrical characteristics of the diode are studied in detail and related to the electroluminescence characteristics. A lower limit for the impact excitation cross section of ª 6x10-16 cm2 is obtained.