Optical and structural properties of Sm-doped SrMoO4 phosphor thin films deposited on sapphire substrates

SrMoO4:Sm3+ phosphor thin films were deposited on sapphire substrates using radio-frequency magnetron sputtering at several growth temperatures in the range of 100 - 400 °C. The effects of growth temperature on the properties of the thin films were investigated using X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectrophotometry, and photoluminescence spectroscopy. The thin films exhibited a tetragonal structure with a dominant (112) diffraction peak, and relatively uniform and hexagonal-shaped particles were observed. The emission spectra under excitation at 276 nm contained four dominant emission peaks located at 567, 606, 650, and 708 nm, respectively. A strong luminescence in the orange-red region with chromaticity coordinates of (0.55, 0.38) was observed for the phosphor thin film deposited at 200 °C. These results suggest that the SrMoO4:Sm3+ phosphor thin film is a promising candidate as a red light-emitting phosphor for use in the fields of displays and lighting.