Visible electroluminescence (EL) is observed at room temperature by current injection intoEu:CaF2layers containing 7.5 and 8.0 at. &percent; Eu grown by molecular beam epitaxy on lightly doped (100)p-type silicon. The EL spectra are broad with peaks near 700 and 600 nm, respectively. Room temperature photoluminescence spectra for the same samples exhibited peaks near 420 nm, with higher doped samples showing a more pronounced long wavelength tail. Although both metal and indium–tin–oxide (ITO) contacts were successfully used for current injection, the best EL intensity stability was achieved with contacts made of a 100 Å thick Al layer covered by a 2500 Å thick ITO layer. ©1997 American Institute of Physics.