Photovoltaics V: amorphous silicon cells: A highly homogeneous amorphous semiconductor material promises low-cost solar cells

A slice of highly refined single-crystal silicon is the primary constituent of nearly all present commercial solar cells. Such cells provide the optimum combination of reliability and efficiency, but they also have a major drawback: high cost, due chiefly to the expense of producing the large crystals of pure silicon. Among the alternative designs being investigated with increasing vigor are solar cells made by depositing thin films of amorphous silicon onto a substrate. The immediate benefits of this approach would be threefold: