Improved blue luminescence in Ag-codoped SrS : Ce thin films made by atomic layer epitaxy and ion implantation

Silver ions were implanted into SrS:Ce3+ thin films grown by atomic layer e pitaxy (ALE) to examine the effects of Ag+ codoping on the luminescence of SrS:Ce3+ used in thin-film electroluminescent (TFEL) devices. High-temperat ure annealing (800 degrees C) of the standard ALE SrS:Ce prepared at 510 de grees C caused a pronounced blueshift of the photoluminescence (PL) emissio n, but the intensity was decreased. Codoping by ion implantation of Ag+ and high-temperature annealing (800 degrees C) caused no further blueshift but the PL intensity was more than double that of the nonimplanted samples. Th e implanted SrS:Ce, Ag also exhibited the longest decay value (S-N = 22 ns at 520 nm with 420 nm excitation) reported for ALE SrS: Ce thin films. The improved PL properties show that codoping with Ag+ can be advantageous in A LE SrS:Ce3+ thin films used for electroluminescent multicolor and full-colo r flat panel displays. The results also suggest the potential of the ion im plantation technique in TFEL device preparation. (C) 1999 American Institut e of Physics. [S0003-6951(99)01716-7].