You can deposit thin films of silicon on to, say, ordinary glass. Usually, this is done with CVD, although I think epitaxial growth is also a popular technique.
The problem is that this tends to produce amorphous silicon, which is not especially efficient. There is a good deal of work to get to the point where monocrystalline silicon thin film cells are viable outside of the lab, though.
The problem is that this tends to produce amorphous silicon, which is not especially efficient. There is a good deal of work to get to the point where monocrystalline silicon thin film cells are viable outside of the lab, though.