Room-temperature luminescence from erbium-doped silicon thin films prepared by laser ablation

We present a useful and simple technique to prepare controllable Er-doped Si thin films using KrF excimer laser ablation. The sharp intense photoluminescence (PL) at 1.54 μm originating from the intra-4f shell transition in Er3+ ions was observed from 18 K up to room temperature. Characteristics of PL thermal quenching and time decay of prepared Er-doped Si thin films are very similar to those of Er-doped porous Si and/or Er-doped amorphous Si. Furthermore, observation of Er3+ emission from as-prepared thin films without thermal annealing suggests that the Er doping in the form of Er atomic radical species produced by laser ablation is essential in activation of Er3+ ions. Moreover, incorporating a prescribed amount of Er in the bulk target enables us to control the Er doping level in thin films prepared by laser ablation.