It is demonstrated room-temperature electroluminescence at 1.54 μm in erbiumimplanted oxygen doped silicon (27 at. 0), due to intra-4f 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 layers deposited onto silicon substrates by chemical vapour deposition of SiH4 and N20, doped by ion implantation with Er to a concentration up to ≈ 1.5 at.%, and annealed in a rapid thermal annealing furnace. The most intense electroluminescence is obtained in samples annealed at 400°C in reverse bias under breakdown condition 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 ≈6×10−16 cm2 is obtained.