Preparation of a Single Layer of Luminescent Nanocrystalline Si Structures by Laser Irradiation Method

KrF excimer laser annealing on ultrathin hydrogenated amorphous Si films with various initial Si thicknesses is carried out to obtain a single layer of nanocrystalline Si structures. It is found that Si nanograins can be obtained with the area density as high as 10¹¹cm^-2 under the irradiation with suitable laser fluence. Raman and planar transmission electron microscopy are used to characterize the formation process of Si nanocrystals from amorphous phase. Moreover, a strong photoluminescence is observed at room temperature from well-relaxed nanocrystalline Si structures.