Spectral photocurrent-voltage characteristics of crystalline silicon and amorphous silicon solar cells

✍ Scribed by W. Kusian; H. Pfleiderer; B. Bullemer

• Publisher: Elsevier Science
• Year: 1987
• Weight: 779 KB
• Volume: 22
• Category: Article
• ISSN: 0379-6787
• DOI: 10.1016/0379-6787(87)90054-8

✦ Synopsis

Crystalline silicon (c-Si) and amorphous silicon (a-Si) solar cells represent complementary cell types. The generation of photocarriers takes place in the semiconductor bulk (c-Si cell) or is confined to the barrier layer (a-Si cell). Carrier collection hence relies on diffusion (c-Si cell) or drift (a-Si cell). We explain the different behavior of the two cell types by measuring photocurrent-voltage characteristics. The photocurrent of the a-Si barrier cell changes its sign at a certain transition voltage UT. We find that UT depends slightly on the light wavelength k but remains invariant with respect to alterations in the light intensity. It is possible to interpret both features in terms of a suitable uniform-field picture for a-Si p-i-n cells. The field through the i layer reverses its sign at the flat-band voltage OF. Avanishing field reveals the small contribution of diffusion to the photocarrier transport. The function UT(h) stems therefore from diffusion.