In-situ determination of the effective absorbance of thinμc-Si:H layers growing on rough ZnO:Al

Abstract

In this study optical transmission measurements were performed in-situ during the growth of microcrystalline silicon (μc-Si:H) layers by plasma enhanced chemical vapor deposition (PECVD). The stable plasma emission was used as light source. The effective absorption coefficient of the thin μc-Si:H layers which were deposited on rough transparent conductive oxide (TCO) surfaces was calculated from the transient transmission signal. It was observed that by increasing the surface roughness of the TCO, the effective absorption coefficient increases which can be correlated to the increased light scattering effect and thus the enhanced light paths inside the silicon. A correlation between the in-situ determined effective absorbance of the μc-Si:H absorber layer and the short-circuit current density of μc-Si:H thin-film silicon solar cells was found. Hence, an attractive technique is demonstrated to study, on the one hand, the absorbance and the light trapping in thin films depending on the roughness of the substrate and, on the other hand, to estimate the short-circuit current density of thin-film solar cells in-situ, which makes the method interesting as a process control tool.

The influence of substrate temperature on the hydrogenated microcrystalline silicon growth through hollow cathode plasma

“…When the temperature is over 200 1C, especially at 300 1C the film growth rate on glass surface is higher than that in ITO coating glass. It is caused from the diffusion of absorbed radical on surface impeded by In metal [19].…”