摘要 :
An investigation was conducted into the effect of hydrogen dilution on the mi-crostructure and optical properties of silicon nanograins embedded in silicon nitride (Si/SiNx) thin film deposited by the helicon wave plasma-enhanced ...
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An investigation was conducted into the effect of hydrogen dilution on the mi-crostructure and optical properties of silicon nanograins embedded in silicon nitride (Si/SiNx) thin film deposited by the helicon wave plasma-enhanced chemical vapour deposition technique. With Ar-diluted SiH4 and N2 as the reactant gas sources in the fabrication of thin film, the film was formed at a high deposition rate. There was a high density of defect at the amorphous silicon (a-Si)/SiNx interface and a relative low optical gap in the film. An addition of hydrogen into the reactant gas reduced the film deposition rate sharply. The silicon nanograins in the SiNx matrix were in a crystalline state, and the density of defects at the silicon nanocrystals (nc-Si)/SiNx interface decreased significantly and the optical gap of the films widened. These results suggested that hydrogen activated by the plasma could not only eliminate in the defects between the interface of silicon nanograins and SiNx matrix, but also helped the nanograins transform from the amorphous into crystalline state. By changing the hydrogen dilution ratio in the reactant gas sources, a tunable band gap from 1.87 eV to 3.32 eV was obtained in the Si/SiNx film.
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摘要 :
Organic devices have many advantages such as low material consumption and low energy requirements, but they have serious issues regarding long term stability. Hence we need to develop a barrier film which solves this problem. Init...
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Organic devices have many advantages such as low material consumption and low energy requirements, but they have serious issues regarding long term stability. Hence we need to develop a barrier film which solves this problem. Initially, the organic devices were fabricated on glass and were encapsulated using glass and epoxy (as sealant). Gradually there was a need to shift on to flexible substrates which required encapsulation to be flexible as well. Therefore, the motivation of the work is to develop thin film encapsulation that can be made flexible. The low temperature PECVD grown films of SiOx and SiNxwere used as the barrier film. Alternate inorganic layers (2-dyads) provided barrier of ~10-2 g/m2 day and increasing the number of dyads to five improved the water vapor transmission rate (WVTR) only by one order of magnitude. However, introducing organic layers in this structure resulted in WVTR value of order 10-5 g/m2 day. The organic layers were deposited by spray technique.
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摘要 :
The friction peak that occurs in tire–road sliding when the contact changes from wet to dry was previously attributed to capillary cohesion,van der Waals attraction,and surface roughness,but the detailed mechanisms have yet to be...
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The friction peak that occurs in tire–road sliding when the contact changes from wet to dry was previously attributed to capillary cohesion,van der Waals attraction,and surface roughness,but the detailed mechanisms have yet to be revealed.In this study,friction and static contact experiments were conducted using a custom-built in situ optical microtribometer,which allowed us to investigate the evolution of the friction,normal load,and contact area between a polydimethylsiloxane(PDMS)film and a silicon nitride ball during water volatilization.The friction coefficient increased by 100%,and the normal force dropped by 30%relative to those in the dry condition during the wet-to-dry transition.In static contact experiments,the probe indentation depth increased,and the normal load decreased by~60%as the water evaporated.Combining the friction and static contact results,we propose that the large friction peak that appeared in this study can be attributed to the combined effects of increased adhesive capillary force and increased plowing during the wet-to-dry transition.
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摘要 :
S1Nx:H films with different N/Si ratios are synthesized by plasma-enhanced chemical vapor deposition (PECVD). Composition and structure characteristics are detected by Fourier transform infared spectroscopy (FTIR) and X-ray photoe...
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S1Nx:H films with different N/Si ratios are synthesized by plasma-enhanced chemical vapor deposition (PECVD). Composition and structure characteristics are detected by Fourier transform infared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It indicates that Si-N bonds increase with increased NH3/SiH4 ratio. Electrical property investigations by I-V measurements show that the prepared films offer higher resistivity and less leakage current with increased N/Si ratio and exhibit entirely insulating properties when N/Si ratio reaches 0.9, which is ascribed to increased Si-N bonds achieved.
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