Characterization of optical transitions by first principles for new photovoltaic materials with isolated metallic intermediate band

Quantum mechanical techniques on the basis of density functional theory have been used to design several novel photovoltaic materials characterized by an isolated metallic intermediate band (MIB), with the potential of achieving an efficiency of 63.2 %. A series of alloy semiconductors of the type: MGa/sub n/As/sub m/ or MGa/sub n/P/sub n/, where M represents a transition metal atom, have been already identified as MIB material. Light absorption in such materials is direct and indirect. Our purpose here is to characterize, using first principles calculations, the matrix elements, the corresponding optical transitions and the phonon dispersion curves for this kind of intermediate band solar cell.