Enhanced Light-graphene Interactions In Visible Wavelengths

Graphene is a two-dimensional mateiral consisted of carbon atoms arrayed inhexagonal lattice. It is a novel semiconductor which is featured with zero bandgap andtherefore processes various excellent features such as high unusual high electronmobility, long carrier life，broadband light absorption and etc. Therefore, it has apromising prospect in fields of solar cells, ultrafast lasers, sensors, and photodetectors.Owing to the potential significant influence on the modern optoelectronic andphotonic industry, the achievement of graphene is honored as Noble pirze for physicsin2010,However, graphene has some intirnsic limits in the application integration. Forexample, the single-atom-thick graphene is difficult to be identified by opticalmicroscope or Raman spectroscopy. Particularly, the interaction between visible lightand graphene is weak and the absorption of visible light is only2.3%, which limits itsapplication in high-performance opto-electrical and photonic devices. Therefore, it isof great importance to enhance the interactions between light and graphene. There aresome solutions to solve the problems. For example, gold nanoparticle arrays and goldnanovoid arrays were used to improve the interaction between graphene and visiblelight. However, such enhancements over broadband wavelength and wide-angle rangeare still challenges today. In this thesis, we address the problem by nanoporous goldstructure (NPG) and silver nanoparticles experimentally.Utilizing the greatly enhanced near-ifelds at proximity of surface by localizedsurface plasmons sustained in NPG and silver nanoparticle structures which are both lack of long-range order, we achieved strong enhancements of interactions betweenlight and graphene over a broadband in wavelength and a wide range of incident angle,resulting in stronger graphene absorption in visible wavelengths and much easierrecognition of graphene by enhanced Raman spectroscopy. Our study shows thatNPG film is a promising platform in novel graphene-integrated applications invisible regime such as photodetectors and light-harvesting devices.