Papers by Keyword: Silicon Nanostructure

Abstract: Silicon-hydrogen crystalline models are proposed to estimate theoretical hydrogen storage capacity in porous silicon media with nanostructure features like cubic nodules, columnar forests and thin wall honeycomb like networks. To simulate these nanostructure features and their hydrogen storage capacities, three basic crystalline types (cubic, column and plate) have been developed as building blocks for constructing H-Si weight storage models under the assumption of that hydrogen is chemically bonded to available surface silicon atoms. Using these models, the hydrogen weight storage capacity for all feature dimensions from unit to infinitely long can be estimated. According to these theoretical models, the best nanostructure for hydrogen storage is cubic nodule, columnar forest and thin wall network in that order. They have weight storage capacity limits of 5.77%, 5.21% and 2.78% respectively for infinitely large feature dimensions.

Abstract: This paper presents the results of PL spectrum studies for Si nano-crystallites embedded in amorphous silicon matrix. Investigated layers were deposited by the hot-wire CVD method on glass substrates at the wafer temperature 300°C and different filament temperatures from the range 1650-1950°C. It was shown that variation of temperatures of filament (hot-wire) allows to produce the films with desirable parameters. Using of X-ray diffraction and photoluminescence methods the correlation between some photoluminescence bands and the sizes of Si nano-crystallites as well as the amorphous phase volume was shown. The nature of light emission is discussed.

Abstract: The aging process of silicon nanostructures obtained by magnetron sputtering and electrochemical etching is investigated by photoluminescence and Raman scattering methods. It is shown that oxidation of silicon crystallites takes place in both types of structures and results in appearance of additional emission bands. However the degree of oxidation in etched structures exceeds significantly this value for sputtered samples. It is found that the intensity and spectral position of the emission band caused by exciton recombination in Si crystallites do not change practically during aging in sputtered structures in contrast to etched ones. It is shown that the oxidation of silicon amorphous phase occur during aging in sputtered structures.