Temperature-dependent photoconductivity of Ce³⁺-doped SrAl ₂O₄

Long persistence SrAl₂O₄:Ce³⁺ single-crystal fibers were prepared using laser-heated pedestal growth method. Four 5d levels split due to crystal field were found in excitation spectrum with peaks at 3.65, 3.87, 4.26, and 4.79 eV, respectively, and the Ce ³⁺ emission band was observed at 3.22 eV in this host. Temperature-dependent photoconductivity was performed. The results from the photoconductivity measurements indicated that the four 5d manifolds were located at 1.3, 0.5, 0.1, and -0.1 eV (±0.05 eV), respectively, relative to the bottom of the host conduction band. The Ce³⁺ ground state was then calculated at 2.7 eV above the host valence band.