Color Tuning of Light Emitted from the Cathodoluminescence of (Ca1 − xEux)Ga2S4 Phosphors

摘要

(Ca1‐xEux)Ga2S4 (x?=?0.10, 0.40, 0.70, 1.0) phosphors were synthesized from CaS, EuS, and Ga2S3 via a solid‐state reaction, and their crystal structures were investigated by X‐ray diffraction analysis. Cathodoluminescence (CL) spectra of these phosphors under moderate electron‐beam voltages from 4 to 10 kV were investigated to assess their applicability in carbon nanotube field‐emission displays. The wavelength at maximum intensity (λmax) of the CL spectra changed gradually from 557 to 546?nm with increasing europium‐ion mole fraction (x) in the (Ca1‐xEux)Ga2S4 phosphors. These bands were attributed to the transitions from the lowest energy level of the 4f65d1 excited state to the 4f7 (8S7/2) ground state of the Eu2+ ions. The blue shift of this wavelength was interpreted on the basis of the crystal structures of the phosphors. The color of light emitted from the (Ca1‐xEux)Ga2S4 phosphors was confirmed to be tunable.