Forming delocalized intermediate states with realistic quantum dots

Experiments and theoretical models suggest that the performance of intermediate band solar cells based on quantum dots (QDs) will be enhanced by the formation of delocalized intermediate bands. However, reasonable device performance has only been achieved when the QD separation is large and energy states are localized to individual QDs. In this paper we analyze the formation of delocalized bands in a realistic QD material that has inhomogeneously distributed energy levels. We calculate the QD uniformity or barrier thickness necessary to create delocalized states in realistic materials and propose a design to create delocalized states while including strain balancing layers. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691113]