Survey of intermediate band material candidates

A systematic ab initio study, using the local spin density approximation, of the electronic properties of GaxPyM compounds, where M is a transition metal substituting Ga or P atoms in a GaP host semiconductor lattice is presented. This study is oriented towards the early identification of intermediate band materials of recent interest as new photovoltaic materials to exceed the efficiency of single gap and even tandems of two solar cells. M=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn have been explored as transition metals and Sc, V, Cr, and Fe in Ga32P31M and Cr in Ga31P32M have exhibited the desired intermediate band.