Fabrication of luminescent Ge nanocrystals started from unlayered hydrogenated amorphous SiGe films or hydrogenated amorphous Si hydrogenated amorphous Ge multilayers

Nanocrystalline Ge embedded in SiOx matrix is fabricated by oxidizing hydro genated amorphous Sice alloys or hydrogenated amorphous Si/hydrogenated amo rphous Ge multilayers. The structures before and after oxidation are system atically investigated. Visible light emission was observed from both sample s. The luminescence peak is located at 2.2 eV which is independent of the s tarting materials. Compared to the luminescence from unlayered samples, the photoluminescence spectrum from multilayered samples has a narrower band w idth, which can be attributed to the uniform size distribution. The light e mission origin is also discussed briefly and a mechanism different from the quantum size effect is suggested.