Si texturing with sub-wavelength structures [solar cell production]

Si solar cell surface reflection has been investigated with textured structures smaller than the optical wavelengths. This physical optics approach relies upon absorption through a waveguide mechanism, and has been realized for both uniform and random structures. Laser interferometric lithography techniques have been combined with conventional wet and reactive ion etching of Si to form a wide range of nanoscale 1-D and 2-D structures in both single and polycrystalline Si substrates. Maskless reactive ion etching of Si has also been employed to form highly absorptive nanoscale structures. For identically etched structures, uniform structures showed an order of magnitude smaller reflectance than random structures.