Luminescent properties of blue-emitting CaS:Cu,F thin films

Abstract

Structural and luminescent properties of CaS:Cu,F thin films prepared by the electron beam evaporation have been investigated. The film annealed at higher than 750/spl deg/C showed [110] orientation and the crystallinity of the film was improved with increasing annealing temperature. The annealed films showed spectra with peaks at 435 and 450 nm and broad emission at longer wavelength at room temperature, and the 435 nm emission became dominant by the annealing at temperatures higher than 750/spl deg/C. It was suggested from the measurement of the time-resolved emission spectra that the blue luminescence of not only the phosphor but also the film is not due to D-A pair recombination but due to the intraionic transition in the Cu/sup +/ ion.