Fabrication and Performance of ACTFEL Display Devices Using Manganese-Doped Zinc Germanate as a Green-Emitting Electroluminescent Layer

Abstract

Alternating-current thin-film electroluminescent (ACTFEL) display devices fabricated using manganese-doped zinc germanate (Zn2GeO4:Mn) as a green-emitting electroluminescent layer material are described. The ACTFEL display devices were fabricated with a standard bottom emission structure having a multilayer stack of thin films in the metal/semiconductor/insulator/ metal (MSIM) configuration. The device was constructed on a transparent Corning glass substrate through which the emitted EL light passed. The Zn2GeO4:Mn emission layer was synthesized by using a RF magnetron sputter deposition method, followed by post-annealing at 700 C in air ambient for 1 hour. The obtained Zn2GeO4:Mn films were found to be polycrystalline with a rhombohedral crystal structure. A green emission spectrum with a maximum at approximately 538 nm was produced from the fabricated device. The chromaticity color coordinates of the EL emission were measured to be x = 0.308 and y = 0.657. The device demonstrated a sharp increase in the intensity of green EL emission upon increasing the AC peak voltage applied to the device above a threshold of 148 V.