Photoluminescence and electroluminescence characteristics of CaSiN2:Eu phosphor

Photoluminescence and electroluminescence of CaSiN2:Eu materials were investigated to develop a new phosphor for thin film electroluminescence (TFEL) device applications. Ca3N2 and Si3N4 powders were mixed to form CaSiN2 host materials and Eu was added as the luminescent center. The mixed powder materials were cold pressed under the pressure of 1Kg/cm(2) to make pellets, and fired at 1400 degrees C for 2 hours under N-2/H-2 environment. The X-ray diffraction (XRD) patterns of synthesized materials were well matched with CaSiN2 of joint committee for powder diffraction standards (JCPDS) card. When illuminated by ultraviolet rays, the new phosphors emitted very bright red light of peak wavelength centered at 620 nm. The TFEL devices with CaSiN2:Eu phosphor layers were grown by sputter deposition of CaSiN2:Eu target. Red light emission was observed when the peak amplitude of the applied voltage exceeded 116V. The luminance was shown to increase sharply with the increase of the applied voltage. The maximum luminance was 1.62 Cd/m(2) at the applied peak voltage of 276V. The red emission from CaSiN2:Eu TFEL device seems to result from electronic transition of Eu3+ ions. The emission spectra of TFEL devices match well with the photoluminescence spectra of CaSiN2:Eu powders. The new devices structure and fabrication processes for the improvement of emission intensity of CaSiN2:Eu TFEL devices are under investigation.