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Hydrogen effusion from hydrogenated amorphous silicon (a-Si:H) and amorphous silicon carbide (a-Si 1− x C x :H) thin films during a temperature ramp between RT and 600 °C was studied by in situ real-time elastic recoil detection analysis. Point to point contour maps show the hydrogen depth profile and its evolution with the ramped temperature. This paper proposes a diffusion limited evolution model to study H kinetic properties from total retained H contents recorded in a single ramp. In a compact a-Si:H layer where H predominantly effuses at high temperatures between 500 and 600 °C, an activation energy value of ∼1.50 eV and a diffusion pre-factor of 0.41 × 10 −4 cm 2 /s were obtained. Applied to an non-stoichiometric a-Si 1− x C x :H film in the same range of temperature, the model led to reduced values of activation energy and diffusion prefactor of ∼0.33 eV and 0.59 × 10 −11 cm 2 /s, respectively. [ABSTRACT FROM AUTHOR]

Nanostructured thin silicon-based films have been deposited using the hot-wire chemical vapour deposition (HWCVD) technique at the University of the Western Cape. A variety of techniques including optical and infrared spectroscopy, Raman scattering spectroscopy, X-rays diffraction (XRD) and transmission electron microscopy (TEM) have been used for characterisation of the films. The electrical measurements show that the films have good values of photoresponse, and the photocurrent remains stable after several hours of light soaking. This contribution will discuss the characteristics of the hydrogenated nanocrystalline silicon thin films deposited using increased process chamber pressure at a fixed hydrogen dilution ratio in monosilane gas. [ABSTRACT FROM AUTHOR]

Using the method proposed by Swanepoel (J Phys E: Sci Instrum 17:896–903, 1984), a-Si:H and nc-Si:H thin films have been successfully characterised using the transmission spectrum alone as taken in the UV–visible range. The studied samples were deposited on both Corning glass and Polyethylene napthalate (PEN) substrates using the Hot Wire Chemical Vapour deposition technique (HWCVD). Results on refractive index, absorption coefficient and energy gap will be presented. Thicknesses calculated by the same method will be compared to those obtained by direct measurement using a Dektak profilometer. [ABSTRACT FROM AUTHOR]

Abstract: Results of photoresponse, activation energy and light soaking measurements on selected hydrogenated nanocrystalline Si thin films are presented. The films were deposited by hot-wire chemical vapour deposition. Values of photoresponse better than 1×102 were obtained. They are lower for porous material as the crystalline volume fraction increases. Activation energy results are related to the intrinsic character and the microstructure of the films. Light soaking experiments show that the nanocrystalline films are very stable. Their amorphous counterparts attain a stable photoconductivity value after 300 h of illumination. [Copyright &y& Elsevier]