Er doped Si layer structures have been grown using Er2O3 Or ErF3 as evaporation source materials during Si molecular beam epitaxy. By using a low temperature growth process, an Er doping level of similar to 5 x 10(19)/cm(3) has been achieved without precipitation. Structural and luminescence properties of these Er/O and Er/F doped Si samples have been studied. Electroluminescence (1.54 mu m) has been observed from Er/O doped Si layers at room temperature through hot electron impact excitation. Comparison of the photo- and electroluminescence of these Er-doped Si structures has been made. The major thermal quenching behaviors of both luminescence emissions are characterized by the same activation energy value of similar to 160 meV, but different on-set temperatures.