Photon and electron excitation of rare-earth-doped amorphous SiN films

Room temperature visible photo and cathodoluminescence have been achieved from amorphous (a-)SiN films independently doped with Pr3+, Sm3+, Dy3+, Ho3+, and Er3+ ions. The films were deposited by co-sputtering a Si target partially covered with metallic rare-earth (RE) in an atmosphere of pure nitrogen. As a consequence of the deposition method and conditions, the films have an amorphous structure and RE contents of 0.5 at.%, as determined by Raman scattering and ion beam analysis, respectively. The luminescence experiments were carried out in films, typically 0.5 μm thick, after excitation with either 488.0 nm photons or 15 keV electrons. All characterizations were accomplished at room temperature and on as-deposited samples. A detailed investigation of the luminescence spectra allowed the identification of all existing optical features and indicates possible RE ion excitation–recombination mechanisms. In addition to the importance of Si in modern (micro-)electronics, the current experimental findings suggest the potential of RE-doped SiN compounds to opto-electronic devices operating in the visible energy range.