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 luminescent properties of ZnS:Mn-based electroluminescent structures are investigated. The beneficial increase of the number of active luminescent centres is assessed via sub-bandgap photoluminescence analysis and an optimum is determined due to the competition of the annealing and ablation processes. The maximal photoluminescence signals obtained via laser treatment are 67% and 19% greater than the signals obtained from samples thermally annealed for 1 h at 5008C and 7008C, respectively. Under certain irradiation conditions, the electroluminescence analysis of laser-annealed samples also shows enhanced values compared with samples treated thermally at 5008C. However, these improvements do not reflect those expected from the photoluminescence analysis. We suggest that multiple pulse irradiation leads to detrimental modifications at the electronic interface for electroluminescence applications. q2000 Published by Elsevier Science B.V. All rights reserved.