Low-field electroluminescence

Fig. 50. GaAs. Ei diode structure for the low-field electroluminescence (from Rolland et al. 1988).

The electroluminescence (EL) process is defined as light generation by an application of an electric field. Two types of EL behavior can be distinguished according to the voltage applied low-field EL, called direct current electroluminescence (DC EL), and high-field EL, called alternating current electroluminescence (AC EL) [19]. 

In the past, significant attention has been paid to the nanophosphors based photoluminescent as well as displays with improved features of higher resolution, lower dose rates and low voltage electroluminescence operation (10 V). However, the work on the devices is still at laboratory scale and it needs efforts to streamline reliability and reproducibility aspects where by multicoloured displays based on low voltage EL may replace plasma display panels, field emission display devices, etc. in near future. 

Unlike thin film transistors, electroluminescence devices operate in a high electric field, and therefore homogeneity and low defect density of the thin films are more important than the carrier transport characteristics. In this sense, the approach to the use of nematic semiconductors by Kelly and O Neill should be reasonable. 

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