Numerical modeling of the intermediate band and transition energy in GaAs/Al<inf>x</inf>Ga<inf>1−x</inf>As quantum dots solar cell with the finite difference approach

Abstract

In this paper, a numerical approach calculating the intermediate band levels, the inter-band and intra-band transition energy in quantum dot intermediate band solar cell, QD-IBSC is presented. We consider the structure of a spherical quantum dots made of GaAs embedded in a Al x G 1−x As matrix. The finite difference approach is used to solve the time-independent Schrodinger's equation of a spherical quantum dot. The resultant Hamiltonian matrix is diagonalized to obtain the energy levels of confined carriers for electron (hole) in conduction (valence) band. The intermediate band energy levels and transition energies are plotted as function of the dot radius for the Aluminum concentration x=0.33. Our result shows that: energy level for intermediate band (i) decreases as the dot radius increases. We also find that: (i) the inter-band transition energy decreases as the dot radius increases (ii) the inter-sub band transition energy increases as the dot radius increases. The obtained results are compared with recent experimental and theoretical works.