Graphene　films　with　different　structures　were　catalytically　grown　on　the　silicon　substrate　pre-deposited　with　a　gold　film　by　hot　filament　chemical　vapor　deposition　under　different　conditions,　where　methane,　hydrogen　and　nitrogen　were　used　as　the　reactive　gases.　The　morphological　and　compositional　properties　of　graphene　films　were　studied　using　advanced　instruments　including　field　emission　scanning　electron　microscopy,　micro-Raman　spectroscopy　and　X-ray　photoelectron　spectroscopy.　The　results　indicate　that　the　structure　and　composition　of　graphene　films　are　changed　with　the　variation　of　the　growth　conditions.　According　to　the　theory　related　to　thermodynamics,　the　formation　of　graphene　films　was　theoretically　analyzed　and　the　results　indicate　that　the　formation　of　graphene　films　is　related　to　the　fast　incorporation　and　precipitation　of　carbon.　The　electron　field　emission　(EFE)　properties　of　graphene　films　were　studied　in　a　high　vacuum　system　of　similar　to　10(-6)　Pa　and　the　EFE　results　show　that　the　turn-on　field　is　in　a　range　of　5.2-5.64　V　mu　m(-1)　and　the　maximum　current　density　is　about　63　mu　A　cm(-2)　at　the　field　of　7.7　V　mu　m(-1).　These　results　are　important　to　control　the　structure　of　graphene　films　and　have　the　potential　applications　of　graphene　in　various　nanodevices.　(C)　2013　Elsevier　B.V.　All　rights　reserved.