The effects of multiple KrF laser irradiations on the electroluminescence and photoluminescence of rf-sputtered ZnS : Mn-based electroluminescent thin film devices

Multiple pulse KrF laser annealing and ablation effects upon the luminescen t properties of ZnS:Mn-based electroluminescent structures are investigated . The beneficial increase of the number of active luminescent: centres is a ssessed via sub-bandgap photoluminescence analysis and an optimum is determ ined due to the competition of the annealing and ablation processes. The ma ximal photoluminescence signals obtained via laser treatment are 67% and 19 % greater than the signals obtained from samples thermally annealed for 1 h at 500 degrees C and 700 degrees C, respectively. Under certain irradiatio n conditions, the electroluminescence analysis of laser-annealed samples al so shows enhanced values compared with samples treated thermally at 500 deg rees C. However, these improvements do not reflect those expected from the photoluminescence analysis. We suggest that multiple pulse irradiation lead s to detrimental modifications at the electronic interface for electrolumin escence applications. (C) 2000 Published by Elsevier Science B.V. All right s reserved.