Green Electroluminescence in Low-Voltage-Driven Metal-Insulator-Semiconductor Structure Devices

Publisher Website
Google Scholar
Abstract
Changes in emission waveforms and brightness with variations in emitting or insulating film thickness have been investigated in Metal-Insulator-Semiconductor (MIS) structure thin-film electroluminescent (TFEL) devices, such as Glass/In2O3/ZnS:TbF3/Sm2O3/Al. It is found that the decrease in brightness with decreasing ZnS layer thickness can be compensated by an increase in brightness obtained by reducing the insulator thickness, and the emission intensity ratio with regard to the applied voltage polarity (P (Al-)/P (Al+)) is proportional to the film thickness ratio of the emitter and the insulator (d Z/d I), in MIS-TFEL devices. Under the optimal condition d Z/d I=1∼2, when P (Al-)≃P (Al+), bright green electroluminescence of 400 fL and 830 fL with threshold voltages of 37 V and 57 V, respectively, are obtained under 5 kHz sinusoidal voltage excitation.