Electronic and hole spectra of layered systems of cylindrical rod arrays: Solar cell application

We have computed the electronic and hole spectra of a three-dimensional superlattice consisting of layers of GaAs rods of finite height arranged in a hexagonal lattice and embedded in an AldGa1−dAs matrix, alternating with spacer layers of homogeneous AlAs. The spectra are calculated in the envelope function approximation, with both light-hole and heavy-hole subbands and hole spin degeneracy taken into account. The application of thick spacers allows to investigate the band structure of isolated layers of cylindrical rods. We estimate the ultimate efficiency of solar energy conversion in a solar cell based on an array of cylindrical quantum dots versus the dot height, and determine the optimal value of this parameter.