Enhanced absorption and quantum efficiency in locally modified single-crystal Si

The experimental collection efficiency of a nanoscale Si-layered system formed around a buried amorphization is investigated. A self-consistent calculation that takes into account the number of photons removed in the front deactivated zone and those transmitted to deeper layers leads to the result that more than one electron per absorbed short-wavelength photon is collected in the active zone lying below a carrier collection limit. This result suggests that it could be possible to make an efficient third generation Si solar cell based on such a design on the condition that photocarriers generated in the surface zone be collected.