Abstract
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.
Highlights
Hot-wire chemical vapour deposition, known as catalytic chemical vapour deposition, is one of the techniques used to prepare thin amorphous and microcrystalline films for photovoltaic and large-area electronic applications.[1,2,3,4] The process involves the catalytic decomposition of the feed gases over a resistively heated filament followed by a deposition of a layer on a substrate kept in an evacuated chamber
The crystal sizes observed from transmission electron microscopy (TEM) fell in the calculated range of about 2–40 nm as determined by the Scherrer formula on X-rays diffraction (XRD) data
When the hydrogen dilution ratio was increased to 92%, a gradual increase of the process pressure allowed the crystallisation of the films at a much lower pressure of 30 μbar
Summary
Hot-wire chemical vapour deposition, known as catalytic chemical vapour deposition, is one of the techniques used to prepare thin amorphous and microcrystalline films for photovoltaic and large-area electronic applications.[1,2,3,4] The process involves the catalytic decomposition of the feed gases over a resistively heated filament followed by a deposition of a layer on a substrate kept in an evacuated chamber. When silane or a silane/hydrogen mixture are used as feed gases, films ranging from amorphous to polycrystalline hydrogenated silicon can be obtained by proper control of the deposition parameters such as the hydrogen dilution ratio in the silane gas,[5] the substrate and filament temperature[4,6] and the process pressure. Hydrogenated nanocrystalline silicon (nc-Si:H)-based devices have been reported to be more stable than their amorphous (a-Si:H) counterparts.[7] Klein et al.[8] have recently shown that microcrystalline silicon films grown at a high deposition rate could be obtained at a high deposition pressure, but the material quality decreased. Good-quality intrinsic nanocrystalline silicon films have been deposited using the increase of the deposition pressure at deposition rates as high as 4.7 s–1
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
