Protocrystalline
A protocrystalline phase is a distinct phase occurring during crystal growth which evolves into a microcrystalline form. The term is typically associated with silicon films in optical applications such as solar cells.Applications
Silicon solar cells
Amorphous silicon is a popular solar cell material owing to its low cost and ease of production. Owing to disordered structure, its absorption extends to the energies below the band gap resulting in a wide-range spectral response; however, it has a relatively low solar cell efficiency. Protocrystalline Si also has a relatively low absorption near the band gap owing to its more ordered crystalline structure. Thus, protocrystalline and amorphous silicon can be combined in a tandem solar cell where the top thin layer of a-Si:H absorbs short-wavelength light whereas the longer wavelengths are absorbed by the underlying protocrystalline silicon layer.
