Strong blue and violet photo- and electroluminescence from Ge- and Si-implanted silicon dioxide

The photoluminescence (PL) and electroluminescence (EL) properties of Ge-implanted SiO₂ films thermally-grown on a Si substrate have been investigated and compared to those of Si-implanted SiO₂ films. It is found that the blue-violet PL from both Si and Ge-rich layers reaches a maximum after annealing at 500°C for 30 min. The PL and EL from Ge-implanted SiO₂ are distinctly higher than that from Si-implanted layers and well visible for the naked eye. The EL spectrum from the Ge-implanted oxide annealed at 1000 °C correlates very well with the PL one and shows a linear dependence on the injected current. The neutral oxygen vacancy is assumed to be responsible for the observed luminescence. In the case of Ge the microstructure after high temperature annealing is studied.