LiF film enhanced high brightness blue electroluminescence of diamond /CeF3 composite film

Abstract

Diamond/CeF3 composite film (DCCF) and diamond/CeF3/LiF composite film (DCLCF) electroluminescent(EL)devices were deposited on n-type heavy-doped silicon substrates by using microwave plasma chemical vapor deposition system (MPCVD) and vacuum electron beam vapor deposition system (EBVD). A series of corresponding tests characterized the composition, microstructure, and EL characteristics of the devices. The experimental results show that the LiF layer can effectively enhance the blue light emission intensity of the composite film device. Blue light emission can be observed in the two types of devices when the forward bias is applied, and the EL spectra of both devices show a strong wide peak at 440 nm. Meanwhile there is no significant difference in the maximum luminous intensity between them. However, when the reverse bias voltage is applied to the two devices, it is found that DCCF device hardly observes visible light emission, while the blue light emission of DCLCF device is very strong. And the EL spectrum of DCLCF device still shows a strong wide peak at 440 nm, and the blue light emission can reach the maximum at 350 V reverse bias voltage. Its maximum luminous intensity is 3.5 times that of DCCF devices, and its brightness can reach 35 cd/m2.