PHYSICS AND TECHNOLOGY OF THIN-FILM ELECTROLUMINESCENT DISPLAYS

The underlying physics involved in the industrially produced yellow emitting thin-film electroluminescent devices (TFELD) with ZnS:Mn as the active material is reviewed and the aspect of newly emerging solutions for full colour TFELDS is considered. This review concentrates on the importance of the concept of loss-free acceleration for the understanding of high light generation efficiency. Some implications for the basics of high-field electronic transport are mentioned: the range of field strengths and times involved seems to be difficult to treat within the idea of band structures. Other basic features of any understanding of the device are the impact excitation of inner shell transitions, energy transfer and cross relaxation within the dopant system, and tunnel emission from interface states, required to occur with high densities at a suitable depth. From formulae, based on the so-called simple model of TFELD, the operating parameters, and their limits and expected margins are derived. A bright future for full colour TFELDS is forecast.