Crystalline composition of silicon deposited on a low-cost substrate for photovoltaic applications studied by in-situ spectroscopic ellipsometry

This paper deals with the study of thin silicon films deposited by plasma-enhanced chemical vapor deposition on the industrial iron-nickel alloy substrate. This approach is promising for fabrication of low-cost high-efficiency solar cells. The main aim is to characterize the intrinsic hydrogenated microcrystalline silicon layer which fulfills its role of the absorber and has a direct impact on the solar cell performance. The real-time ellipsometric data obtained during the material deposition in the reactor are used to study the composition of the grown material. Based on the designed optical model, the evolution of the material crystallinity as well as the thickness and composition of the surface roughness layer are established in addition to an estimation of the average growth rate. Transmission electron microscopy was used to obtain the images of material structure and to verify conclusions of optical modeling.