THE RELATION BETWEEN LUMINOUS PROPERTIES AND OXYGEN-CONTENT IN ZNS-TBOF THIN-FILM ELECTROLUMINESCENT DEVICES FABRICATED BY RADIOFREQUENCY MAGNETRON SPUTTERING METHOD

The purpose of this paper is to study the relationship between the oxy gen concentration and brightness degradation in ZnS:TbOF green thin-fi lm electroluminescent (EL) devices, The characteristics including crys tallinity, optical, and electrical properties were discussed, The brig htness-voltage (B-V) measurement results showed that with higher oxyge n-content in ZnS:TbOF phosphor layer, lower brightness was measured, I t Was consistent with the poor crystallinity, worse photoluminescent i ntensity, and easier to get moisture in the oxygen-rich (O/Tb > 1) pho sphor film, Furthermore, deep level transient spectroscopy (DLTS) meas urements identified that when the O/Tb ratio was greater than 1, the o xygen-related deep hole traps E-H1 and/or E-H2 could be detected in th e ZnS:TbOF phosphor layer, These E-H1 and/or E-H2 traps were believed to be the main killers for the brightness of the device since they cap ture most of the holes from the generated electron-hole pairs, This ev idence strongly supports that the modified energy transfer model is mo re dominant than direct impact excitation during the luminescent proce ss.