Giant enhancement of ultraviolet near-band-edge emission from a wide-bandgap oxide with dipole-forbidden bandgap transition

Abstract We report giant enhancement of recovered ultraviolet near-band-edge emission from SnO 2 thin films with dipole-forbidden bandgap transition via Ag-doping and surface plasmon coupling. It is found that a recovering near-band-edge emission in the range of 361–375 nm in a low-concentration Ag-doped SnO 2 film, suggesting that dipole-forbidden transition rule of SnO 2 is broken. First-principles electronic structure calculations indicate that the breaking of the dipole-forbidden transition rule is derived from the acceptor of Ag substituting Sn in SnO 2 . 30-fold enhancement of ultraviolet near-band-edge emission from the Ag-doped SnO 2 film is observed by modifying film surface using Ag nanoparticles. The giant enhancement of ultraviolet emission is ascribed to surface plasmon coupling between Ag-doped SnO 2 and Ag nanoparticles. Our results suggest that Ag doping and Ag nanoparticles surface modification in SnO 2 films play important roles in recovering and enhancing ultraviolet emission of SnO 2 with dipole-forbidden bandgap transition.