High-performance broadband photodetectors have recently attracted signicant interest because of their importance to a variety of applications,including imaging,remote sensing,environmental monitoring,astronomical detection,photometers and analytical applications.Reduced graphene oxide(RGO)obtained by chemical exfoliation from graphite has a natural energy gap,which can be tuned by controlling the degree of RGO reduction [1].The apparent energy gap ranged from 10 to 50 meV and approached zero with extensive reduction.