Low-voltage DC electroluminescent device using semiconductive band barriers with Cu2O

To improve the efficiency of a DC Electroluminescent (DC-EL) device, we investigated the reduction of the driving voltage while maintaining the stability of the DC-EL device in this study. Mechanisms for both the current control and hot-electron generation under low voltage were embedded in the device. Usage of a p-Cu2O thick film with high-performance electrical properties for the formation of two semiconductive band barriers in series achieved these functions. The n-ZnO/p-Cu2O controlled current, and the p-Cu2O/n-ZnS:Mn generated hot electrons. The electrical characteristics of each junction demonstrated those of the p-n junction, and the driving voltage was divided into both the junctions. 98% of the driving voltage was applied to the hot-electron generation junction. Electroluminescence was obtained at approximately 20 V, because the local electric field at the junction accelerated electrons. Although the luminance was insufficient, it has been inferred that such a device structure is effective in decreasing driving voltage.