Enhancing light emission of Si nanocrystals by means of high-pressure hydrogenation.

High-density Si nanocrystal thin film composed of Si nanocrystals and SiO, or Si-NCs:SiO, was prepared by annealing hydrogen silsesquioxane (HSQ) in a hydrogen and nitrogen (H:N=5%:95%) atmosphere at 1100°C. Conventional normal-pressure (1-bar) hydrogenation failed to enhance the light emission of the Si-NCs:SiO sample made from HSQ. High-pressure hydrogenation was then applied to the sample in a 30-bar hydrogen atmosphere for this purpose. The light emission of Si-NCs increased steadily with increasing hydrogenation time. The photoluminescence (PL) intensity, the PL quantum yield, the maximal electroluminescence intensity, and the optical gain were increased by 90%, 114%, 193% and 77%, respectively, after 10-day high-pressure hydrogenation, with the PL quantum yield as high as 59%, under the current experimental condition.