The TbOF Complex Center and the Brightness of ZnS Thin-Film Green Electroluminescent Devices

Abstract

Tb- doped ZnS thin-film is a promising material for practical green electroluminescent (EL) panels. Recently, the brightness of the green EL panels has been increased considerably [1–4]. This is mainly due to sputtering. At initial stage of development, the main advantage of sputtering is thought to be a capability of uniform doping of the emission centers of TbF3 molecules into the ZnS host [1]. Further research has revealed that the advantage of the sputtering is not only uniform doping of the emission centers but also creating efficient TbF emission centers in the ZnS host [5,6]. The EL device having TbF complex centers, which are formed during the sputtering, exhibits bright green EL. The TbF complex center consists of a substitutional Tb atom in the Zn site with a F atom in the nearest interstitial site [5]. Furthermore, we have found that oxygen doping plays an important role in obtaining high brightness [7]. In this paper, we will report our experimental results indicating that F/Tb atomic ratio is very important in obtaining high brightness, and additional doping of oxygen to the TbF complex center is very effective in further improvement. The mechanisms of these improvements are also discussed.KeywordsOxygen Partial PressureComplex CenterEmission CenterHigh LuminanceSubstitutional ImpurityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.