Efficient blue-LEDs with a MgO layer as interfacial modification layer

Abstract

Novel blue light-emitting diodes (LEDs) based on nanostructured ZnSe/ZnS multilayer thin films are demonstrated. By introducing a thin MgO film as an interfacial modification layer, the performance of the devices have been significantly improved. Both photoluminescence and electroluminescence intensity are enhanced. The electroluminescence intensity is up to about 3 times higher than that of the LEDs without MgO layer. The optimum thickness of the MgO layer is about 10 nm. On the one hand, the thin MgO layer can improve the crystallization quality and compactness of the nanostructured multilayer films. On the other hand, the MgO layer can not only block holes to balance charges concentration but also provide a preferable inter-face for suppressing excitons quenching. Our results indicate that MgO can serve as an effective interfacial modification layer in the field of LEDs.