Possible reduction of the series resistance of a silicon solar cell through the use of a composite built-in field and improved material

Abstract

In order to obtain maximum benefit of concentrated solar radiation, the skin layer resistance must be reduced. One way is to use a thicker skin layer with means for compensating the adverse effect of recombination; this means is a composite built-in field of proper distribution in the skin region. The composite field comprises a narrow region close to the surface with a field acting toward the surface, and a wide region with a field acting towand the junction. Equations are derived, and it is shown that the efficiency may be doubled or more with a cell having a 15- mu m skin layer, the net rise being 10 while total voltage drop approximates 0.04 V. The series resiatance will be 0.10 of the value of a field-free cell. (DLC)