Improvement of the efficiency of silicon solar cells

The efficiency of a silicon solar cell can be greatly improved as a result of a drastic decrease in the dark current, which is attained by replacing the continuous heavily doped layers for a set of small heavily doped regions, the distances between which are much larger than their size. The effect is caused by the fact that the major contribution to the dark current is provided by surface recombination, which greatly increases with doping near the interface with the insulator. It is shown that there is an optimal relationship for the distances between the regions and their sizes at which the dark current is considerably suppressed, but there is no appreciable decrease in the photocurrent due to deterioration in conditions of minority-carrier collection, and no significant series resistance is introduced. In this case, the operating voltage and efficiency of the solar cell substantially increase.