Strong white and blue photoluminescence from silicon nanocrystals in SiN_x grown by remote PECVD using SiCl_4/NH_3

摘要

Strong white and blue photoluminescence (PL) from as-grown silicon nanocrystals (nc-Si) in SiN_x films prepared by remote plasma enhanced chemical vapour deposition using SiCl_4/NH_3 mixtures is reported. The colour and intensity of the PL could be controlled by adjusting the NH3 flow rate. Samples with white emission were annealed at 1000 deg C, obtaining a strong improvement of the PL intensity with a blue colour. The PL can be attributed to quantum confinement effect in nc-Si embedded in SiN_x- matrix, which is improved when a better passivation of nc-Si surface with chlorine and nitrogen atoms is obtained. The size, density and structure of the nc-Si in the as-grown and annealed films were confirmed and measured by high-resolution transmission electron microscopy.