Er and Cu codoped SiO2 films obtained by sputtering deposition: Enhancement of the rare earth emission at 1.54 μm mediated by metal sensitizers

► PL properties of Er ion doped silica films are improved after Cu ion incorporation. ► 1.54 μm Er PL emission increase is due to a Cu-mediated sensitization mechanism. ► Er ions can be excited via Cu sensitizers with enhanced excitation cross section.