Emitter degradation in quantum dot intermediate band solar cells

The characteristics of intermediate band solar cells containing 10, 20, and 50 InAs quantum dot (QD) layers embedded in otherwise standard (Al,Ga)As solar cell structures have been compared. The short-circuit current densities of the cells decreased and the quantum efficiencies of the devices showed a concomitant reduction in the minority carrier lifetime in the p emitters with increasing number of QD layers. Dislocations threading up from the QDs toward the surface of the cells, and revealed by bright field scanning transmission electron microscopy, are the most likely cause of the deterioration in the electrical performance of the cells. (c) 2007 American Institute of Physics.