Molecular-beam epitaxy growth of strontium thiogallate

The molecular-beam epitaxy growth and characterization of cerium doped strontium thiogallate (SrGa2S4:Ce) thin film phosphors are reported. The layers were grown on GaAs, and glass/indium tin oxide/dielectric stack substrates for device fabrication. Ga2S3/Sr beam equivalent pressure ratios of 20–100 and CeCl3/Sr flux (molecules cm−2 s−1) ratios of 1/20–1/10 were investigated in this study. The substrate temperature was varied between 530 and 575 °C. A typical SrGa2S4:Ce film growth rate of 0.5 μm/h was obtained with Sr, Ga2S3, and CeCl3 beam equivalent pressures of 2.0×10−7, 1.0×10−5, and 3.5×10−8 Torr, respectively. Characterization of the layers’ structural and optical properties by x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, and photoluminescence spectroscopy is presented.