Abstract
Ph.D.
The aim of this study was the development of a new technology for the manufacturing of
amorphous silicon (a-Si:H) solar cells on flexible substrates. Kapton R , a commercially
available polymer, was used as a substrate to this end. The use of such a polymer,
as opposed to glass, results in dramatic savings and also affords the possibility for
technological innovation.
From the start the project was planned to develop and commission a medium-scale
pilot plant manufacturing process. The project thus consisted of two sections: the
design, fabrication and implementation of a large-area deposition system, as well as
research and development of the materials and cells.
A pilot plant was developed and successfully implemented. The optimization of the
reactor resulted in very homogeneous materials with good electrical- and optical characteristics.
The individual materials were optimized and incorporated into the standard
cell configuration (on glass). This process was then transferred to kapton and the
configuration was optimized.
The use of kapton, as opposed to glass, implies the growth of silicon on a metal film
on the kapton. This process leads to a number of phenomena occurring in cells on
kapton which do not occur in standard cells on glass. The phenomena include the
crystallization of a-Si:H at low temperatures, degradation of the material properties
and unwanted microstructure. The origin of these phenomena can be linked to the
high occurence of metal/Si-interdiffusion. It was found that this inter-diffusion can be
decreased by the insert i on of a thin ZnO buffer layer between the back metal contact
and the a-Si:H.
The flexible cells were successfully developed and optimized for large areas. An operational
manufacturing process was thus developed and the product of this study can
now be applied successfully in practical applications.