Analysis of electronic structure in quantum dot arrays for intermediate band solar cells

Intermediate band solar cells (IBSCs) have been proposed as highly efficient third generation photovoltaic devices. Quantum dot (QD) arrays produce mini-bands that are separated by a region of zero density of states from other states in the conduction band. Additional absorption from the valence band to the IB and the IB to the conduction band allows two photons with energies below the energy gap to be harvested in generating one electron-hole pair. We present a theoretical study of the electronic and optical properties of the IB formed by an InAs/GaAs QD arrays. The calculations are based on effective-mass approximation and finite element method. Theoretical results of the mini-band width variation with the period of the QD arrays in the z direction are presented.