engleski

Preparation of SiO/SiO2 superlattice

One approach for silicon based next genration solar cells relies the production of suitable Si nanostructured objects in wide bandgap material. Present research on Si nanosize structures is focused on the Si nanocrystals prepared by sputtering of Si rich oxides and SiO2 multilayers on Si substrates. We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at different elevated temperatures. Grazing-incidence small-angle X-ray scattering (GISAXS), X-ray reflectivity and photoluminescence were used to study such samples. From the 2D GISAXS pattern it is possible to determine the shape, size and inter-particle distance. Amorphous SiO/SiO2 superlattices were prepared by magnetron sputtering or high vacuum evaporation of 2nm thin films of SiO and SiO2 (10 layers each) from corresponding targets on silicon substrate. Rotation of the Si substrate during evaporation enables homogeneity of films over the whole substrate. After evaporation samples were annealed at 1050 C in different atmospheres. The analysis of the 2D GISAXS pattern has shown that some Si nanocrystals are already present in some samples deposited at elevated temperatures. Using a Guinier approximation, the inter-nanocrystal distance and the thickness of the nanocrystals have been obtained. A long range ordering of nanoparticles deposited at elevated temperatures are observed.

Si/SiO2; superlattice

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