Silicon-based light-emitting materials: Implanted Si02 films and wide bandgap a-Si:H

We review critically recent results ofinvestigation ofhydrogenated amorphous silicon (a-Si:H) and Si-implanted Si02 films from the point ofview oflight-emission applications. Wide bandgap a-Si:H with the energy gap ranging from 2.0 to 2.2 eV exhibits room temperature photoluminescence in the visible region. Electroluminescence, however, occurs after previou s recrystallization ofa-Si:H only and seems not to be perspective for large scale applications. Sit-implanted Si02 films contain, after proper annealing at 1000- 1 100 °C, Si nanocrystals that luminesce in the red. In parallel another emission band can occur (in the blue region) which is related to post-implantation defects. We demonstrate that in Si02 films homogeneously implanted across the entire film thickness red electroluminescence can be easily observed, presumably due to injection of electron-hole pairs into Si nanocrystals. Finally, the present status ofprospects of stimulated emission achievement in low-dimensional Si structures is briefly summarized