Temperature-time profile used during the SPC process. After 180 min, the temperature is held constant at 570 °C for 15 h.
Deposition rate of the a-Si:H film as a function of deposition pressure.
FWHM of the first a-Si:H XRD peak as a function of the deposition pressure of the a-Si:H film. The samples can be grouped into two groups, namely, type A and type B as indicated in the figure.
(a) R*, (b) Avrami exponent, n, (c) average grain size, (d) UV reflectance quality factor Q, as a function of deposition pressure.
SPC dynamics of the a-Si:H thin films for various a-Si:H deposition pressures. Samples deposited at a pressure of ≤ 0.6 Torr (type A) have similar SPC dynamics. Samples deposited at 0.8 Torr and 1.0 Torr (type B) showed significantly shorter incubation times and faster crystallisation rates. The error bars are based on the standard deviation of data points at 100% crystallinity. Solid symbols represent type B samples while hollow symbols represent type A samples.
(a)–(c) HAADF-STEM images of a type A sample (0.6 Torr). (d)–(f) HAADF-STEM of a type B sample (1.0 Torr). Arrows labelled “poly-Si” indicate grains which are aligned for dislocation imaging. Columnar grains were more commonly observed for type A samples than type B samples. Type A samples on average also have grains with lower dislocation densities compared to type B samples.
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