Cathodoluminescence and green-thermoluminescence response of CaSO ₄:Dy,P films

We herein report on the cathodoluminescence (CL) and green- thermoluminescence (TL) emission of CaSO₄:Dy,P films deposited by the spray pyrolysis method at different temperatures. The samples have been previously structurally and chemically characterized by means of Raman spectroscopy and energy dispersive spectroscopy (EDS). The CL spectra show (i) a broad emission band centered at 374 nm that corresponds to the intrinsic emission of (SO₄)^2- and (ii) emission bands centered on 486, 574, 668, 758 nm assigned to the electronic transitions of the Dy ³⁺ ions. The TL glow curves of the films showed three groups of components peaked at around of 98, 152 and 300°C that exhibit a gradual and progressively linear shifting of the T_max as function of T _stop. This TL behavior is related to a continuum in the trap distribution associated with general or multi-order kinetics and involving continuous processes of trapping-detrapping. The activation energy in the range of 0.97-1.53 eV has been estimated using the initial rise method.