We　used　a　193-nm　ArF　excimer　laser　to　produce　a　surface　functional　layer　with　a　tunable　Schottky　barrier　height　(SBH)　on　the　n-type　4H-SiC　surface.　The　SBHs　of　the　laser-modified　layer/SiC　contact　ranged　from　0.38　+/-　0.05　to　1.82　+/-　0.1　eV.　We　evaluated　the　I-V　characteristics　of　Schottky　barrier　diodes　(SBDs)　and　investigated　their　corresponding　nanoscale　current　transport　characteristics　across　the　laser-modified　layer/4H-SiC　interface.　We　attributed　changes　of　the　interfacial　transport　properties　between　Au　and　SiC　to　the　laser-induced　formation　of　SiOx/Si　compounds　with　oxygen　vacancies　in　the　nitrogen-doped　(N-doped)　defective　graphitic　structure.　Density　functional　theory　calculations　suggested　that　defect　oxide　in　the　SiOx/Si　decreased　the　Schottky　barrier　width　and　increased　the　direct　electron　tunneling　current.　Furthermore,　the　Fermi　level　of　the　laser-induced　N-doped　defective　graphitic　structure　shifted　towards　the　conduction　band　compared　with　that　of　pristine　graphene,　which　was　also　beneficial　for　reducing　the　SBH.　This　study　provides　a　novel　understanding　of　the　interfacial　interactions　of　a　laser-modified　layer　on　SiC　through　nanoscale　electrical　analysis.　These　findings　will　be　useful　for　further　investigations　of　SiC-based　nano-photoelectric　devices.