▎ 摘　　要

Effects and mechanisms of conductivity variation of chemically vapor deposited single-layer graphene covering silver nanoparticles on SiO2/Si are reported based on blue-light (405nm) induced plasmonic coupling and electrical current induced annealing and desorption of surface adsorbates. With 1V applied voltage, photoconductivity is positive except a brief negative period when the graphene is first illuminated by light. At 10mV applied voltage, negative photoconductivity persists for hours. In comparison, negative photoconductivity of graphene on pristine SiO2/Si persists for tens of hours. When the applied voltage is increased to 1V, it takes tens of hours of light illumination to change to positive photoconductivity. (C) 2012 Optical Society of America