Nonthermal plasma synthesized freestanding silicon–germanium alloy nanocrystals

Abstract

The composition, structure, light emission and oxidation kinetics ofSi1−xGex alloynanocrystals (∼3 nm in diameter) synthesized by nonthermal plasma have been investigated. It is found thatthe synthesized nanocrystals are neither a mixture of Si nanocrystals and Genanocrystals nor Si–Ge (Ge–Si) core–shell nanocrystals. The H coverage at the surface ofSi1−xGex nanocrystalsdecreases with the increase of the Ge atomic fraction. The incorporation of Ge enhances the oxidationof Si1−xGex nanocrystals when the atomic fraction of Ge is<0.5. No shift in photoluminescence from hydrosilylatedSi1−xGex nanocrystals is observed when the atomic fraction of Ge varies between 0 and 0.1,indicating that the bandgap of Si nanocrystals is similar to that of Ge nanocrystals at ananocrystal size of 3 nm.