▎ 摘　　要

Lanthanum hexaboride (LaB6) is coated on electrophoretically deposited-graphite film by electron beam evaporation method. Surface morphology, Raman spectra and field emission properties are discussed by varying LaB6 coating thickness. It is demonstrated that this film cathode always shows much better field emission performance than pristine graphite cathode. Especially when LaB6 film thickness is 90 nm, the emission current increases from 153 mu A to 850 mu A with the applied electric field of 6.7 V mu m(-1), and the turn-on field decreases from 2.3 V mu m(-1) to 1.0 V mu m(-1). The results suggest that the graphene-based composite is an excellent field emission cathode, especially suitable for vacuum devices such as field emission display.