ABSORPTION-COEFFICIENT OF SILICON - AN ASSESSMENT OF MEASUREMENTS ANDTHE SIMULATION OF TEMPERATURE-VARIATION

The absorption coefficient of crystalline silicon is an important inpu t for designing solar cells and extracting recombination parameters fr om device measurements. Since many contradicting measurements have bee n published, an assessment of data is given based on device measuremen ts and on the discussion of experiments in the literature. An absorpti on coefficient for the ultraviolet to infrared spectral range is propo sed, based on the results of three groups. These data can be described semiempirically by the theory of direct and indirect band transitions . This formulation enables the determination of the optical absorption in crystalline silicon at an arbitrary temperature. The interpretatio n and design of solar cells for operation at temperatures above room t emperature is now possible.