Visible room-temperature emission and excitation photoluminescence in In+- and As+-co-implanted SiO2 films

The visible room-temperature emission and excitation photoluminescence spectra were studied as a function of the indium and arsenic profiles in the In+ and As+ ion-implanted thermally grown SiO2 films before and after the annealing at the temperature of 900 degree celsius. As+ ions at the energy of 40 or 135 keV and In+ ions at the energy of 50 keV, providing a projective range ratio R-p(As)/R-p(In) of 1 or 3, respectively, were used. Four emission photoluminescence bands, peaked at similar to 347 nm (3.57 eV), similar to 440 nm (2.81 eV),similar to 450 nm (2.75 eV) and similar to 500 nm (2.48 eV), were obtained from the 40 keV As+ and 50 keV In+ ion-implanted samples under the excitation wavelength of 300 nm (4.13 eV), 350 nm (3.54 eV), 400 nm (3.10 eV) and 450 nm (2.75 eV), respectively. As the As+ energy increased to 135 keV, under the same excitation conditions, the emission bands peaked at 370 nm (3.35 eV), 420 nm (2.95 eV), 460 nm (2.69 eV) and 505 nm (2.45 eV) dominated in the photoluminescence spectra. The excitation spectra of the observed emission peaks were studied, too. We preliminarily interpret the observed photoluminescence peaks as a result of the T-1 -> S-0 transition of molecular-like clusters associated with the oxygen deficiency provided by In or In-As in ion-implanted SiO2.