GaN　nanofilms　(NFs)　with　different　structures　are　grown　on　SiC　substrates　by　pulsed　laser　deposition　under　different　conditions.　The　synthesized　GaN　NFs　are　studied　by　X-ray　diffraction,　field-emission　(FE)　scanning　electron　microscopy,　X-ray　photoelectron　spectroscopy,　and　atomic　force　microscopy.　The　GaN　NFs　are　composed　of　diversified　GaN　nanoparticles　with　a　diameter　of　9-38　nm,　thickness　of　10-50　nm,　and　roughness　of　0.22-13.03　nm.　FE　from　the　GaN　NFs　is　structure　dependent,　which　is　explained　by　stress　changing　the　band　gap　of　the　NFs.　By　structure　modulation,　the　turn-on　field　of　GaN　NFs　can　be　as　low　as　0.66　V/mu　m　at　a　current　density　of　1　mu　A/cm(2),　with　a　current　density　of　up　to　1.1　mA/cm(2)　at　a　field　of　4.18　V/mu　m.　Fowler-Nordheim　curves　of　some　samples　contain　multiple　straight　lines,　which　originate　from　the　structural　change　and　diversification　of　GaN　nanoparticles　under　an　applied　field.　Overall,　our　results　suggest　that　GaN　NFs　with　excellent　FE　properties　can　be　prepared　on　SiC　substrates,　which　provides　a　new　route　to　fabricate　high-efficiency　FE　nanodevices.　(C)　2014　AIP　Publishing　LLC.