Effect of anion vacancy on the chromacity of luminescence for Sr(S,Se):Ce,Cl thin film electroluminescent devices

Abstract

We report the luminescence characteristics of Sr(S,Se):Ce,Cl thin film electroluminescent devices, fabricated by co-evaporation of SrS:Ce,Cl pellet and elemental Se. From the electroluminescence spectra measurements for varied S:Se mole ratio and temperature, it is found that the relative intensity of green emission band to blue emission band decreases with increasing lattice constant of the host lattice. This can be qualitatively accounted for as being caused by a nonradiative energy transfer from the emission band of Ce3+ to the absorption band due to defects associated with anion vacancies in the host lattice.

XPS and electroluminescence studies on SrS1−xSex and ZnS1−xSex thin films deposited by atomic layer deposition technique

“…Earlier studies on SrS 1Àx Se x :Ce and SrSe:Ce thin films have shown that the addition of Se shifts the main peak of the EL spectrum by B10 nm toward shorter wavelengths as compared to SrS:Ce [2,3,23,24]. Luminance enhancement due to Se addition has been reported only in Ref.…”

“…However, the emission color of SrS:Ce is blue-green, therefore many attempts have been made to shift the emission towards blue. One solution for the more bluish emission has been addition of Se into the SrS host, which has been reported to shift the main emission peak to shorter wavelengths [2,3].…”

“…Until now, electron beam evaporation (EBE) and thermal evaporation have been used in growth of doped Zn(Sr)S 1Àx Se x solid solutions in thin film form [2,3,[6][7][8]. In this study SrS 1Àx Se x (:Ce) and ZnS 1Àx Se x (:Mn) thin films were deposited by the atomic layer deposition (ALD) technique [9].…”