Atomic structure, electronic and optical properties of Si nanocrystals embedded in β-cristobalite and α-quartz

Abstract We use DFT calculations to study the atomic structures, the optical and electronic properties of silicon nanocrystals (nc-Si) embedded in β -cristobalite and in α -quartz matrix. We show that the optical properties are influenced by the matrix type. The energy range of the absorption spectrum of nc-Si in α -quartz matrix is more extended than that of nc-Si in β -cristobalite. The presence of Si–O–Si bridge bonds at the nc-Si/ β -cristobalite interface favours the stability of the system. The energy gap of nc-Si with interface defects is larger than that of nc-Si without interface defects.