Optical confinement and optical loss in high-efficiency a-Si solar cells

The world's highest stabilized conversion efficiency of 9.5% has been achieved for a 30/spl times/40 cm/sup 2/ a-Si/a-SiGe glass superstrate solar cell submodule. However, significant optical loss still exists even in these high-efficiency a-Si solar cells. FEM numerical simulation has shown that the primary origin of the optical loss in textured a-Si solar cells at about /spl ges/800 nm is absorption in SnO/sub 2/ which is enhanced by the optical confinement effect. Optical confinement also results in increased absorption in the metal electrode, which is another source of optical loss.