Abstract
Thin‐film silicon deposited by plasma‐enhanced chemical vapour deposition (PECVD), encompasses both hydrogenated amorphous silicon (a‐Si:H) and ‘nanocrystalline silicon’ (nc‐Si), the latter being a two‐phase mixture of discrete nanocrystallites in an amorphous matrix. It is distinguished from a‐Si:H by a characteristic Raman spectrum. As the film structure moves from amorphous to more crystalline, the Raman TO phonon spectral region no longer consists of a broad amorphous peak at ∼480 cm^−1^ but instead has an obvious narrower peak located at higher wavenumber. The accepted signature peak for nc‐Si lies between these two and most probably arises from the hexagonal, wurtzite structure of the nanocrystals. Here we use Raman spectroscopy to show how the structure of thin‐film silicon on woven polyester is influenced by the substrate as well as by the deposition conditions. We find that the rough surface of the textile substrate enables nc‐Si formation, provided that the correct deposition conditions are employed and that the substrate temperature does not exceed 210 °C. Although the gas mixture is the dominant parameter for determining the film structure, and input power also has a significant effect, we find that a specific combination of these interrelated parameters is essential to control the final structure.