Quantum Confinement Modeling and Simulation for Quantum Well Solar Cells

In this chapter, the authors present the modelling and simulation of the multi-layered quantum well solar cells as well as the simulated results of this model. The quantum confinement of a semiconductor induces new energy levels, located in the band gap, as well as resonant levels located in the conduction and valence bands. These levels allow supplementary absorption in the visible and near infrared range. The quantum efficiency of the supplementary absorption is calculated within the infinite rectangular quantum well approximation. As the absorption excites carriers in the gap of each layer, even a small absorption significantly increases the photocurrent (by photoassisted tunneling) and, therefore, the cell efficiency. The results of the simulation are presented for the internal quantum efficiency of the transitions between the resonant levels of GaAs, as well as the internal quantum efficiency of the transitions between the confinement levels for GaAs and AlxGa1-xAs. New directions for the research of quantum well solar cells are indicated.