Study of the Interface Layers Between Si Nanoparticles and SiO2 Matrix Deposited by e‐Gun Evaporation. Issue 10 (24th March 2018) - Pivac, Branko
Abstract : The structural properties of Si nanoparticles (NPs) formed for application in advanced solar cells are explored. A superstructure consisting of Si NPs is formed after annealing of SiO2 /Si‐based multilayers. The structural properties are explored by GISAXS/GIWAXS and photoluminescence analysis. Both the GISAXS and GIWAXS techniques are simultaneously used to obtain the size and shape of the grown objects, and in addition the GISAXS patterns are analyzed using the Porod theory to obtain information on the Si NPs/matrix interface. The GIWAXS analysis of multilayers with Si layer thickness of 2 or 4 nm confirms that in both cases already after annealing at only 900 °C crystalline particles are created, GISAXS reveals that depending on the initial thickness of the deposited Si layer (2 or 4 nm), the NPs formed after annealing have either sphere‐like (2 nm Si layer) or a combination of sphere and oblate‐like shapes (4 nm). The photoluminescence results support the assumption that the formed defect layer at the Si NP/matrix interface is dominantly responsible for the light emission. We further analyze the GISAXS data in the light of the Porod theory and the results support the model that the formed NPs are surrounded by a defected layer. Abstract : Crystalline Si nanoparticles embedded in amorphous SiO2 matrix are formed after annealing of SiO2 /Si multilayers at 900 °C. Porod analysis of the GISAXS data supports the model that the formed nanoparticles are surrounded by a defected layer at the matrix interface, whose thickness is proportional to the photoluminescence intensity and increases with the size of the nanoparticles.