THE EFFECT OF A LiF LAYER ON Al/LiF/Alq3 INTERFACES STUDIED WITH ELECTRON SPECTROSCOPIES

Abstract
The interface of the tris (8-hydroxyquinoline) aluminum ( Alq 3)/ LiF/Al system was investigated with ultraviolet photoelectron spectroscopy (UPS), metastable atom electron spectroscopy (MAES), and X-ray photoelectron spectroscopy (XPS). Strong chemical interaction was observed at Alq 3 on Al interface. By inserting a LiF layer, this interaction is suppressed and interface energy level alignment is changed to reduce a barrier for electron injection. The enhancement of device efficiency is ascribed to these phenomena. The importance of the combined use of various techniques on the same interface is stressed.