Cathodoluminescence Properties of Red‐Emitting Sr 1− x Ca x S:Eu Phosphors

Sr 1− x Ca x S :Eu ( x  = 0, 0.2, 0.4, 0.6, 0.8, 1) phosphors were prepared from CaS , SrS , and EuS via a solid‐state reaction in air. The cathodoluminescence ( CL ) spectra of the Sr 1− x Ca x S :Eu phosphors for the moderate voltage ranging from 4 to 10 kV were obtained to test their usefulness in field emission displays ( FEDs ). The maximum wavelength of the CL spectra of the Sr 1− x Ca x S :Eu phosphors increases from 629 to 668 nm as the mole fraction of calcium increases up to x  = 0.8, and then decreases to 663 nm at x  = 1. The relationship between the CL spectra and crystal structures of the Sr 1− x Ca x S :Eu phosphors was determined.