Analysis of metallic intermediate-band formation in photovoltaic materials

The substitution of some transition atoms in III-V-type semiconductors may give rise to a type of high-efficiency photovoltaic material with an isolated intermediate narrow band in the middle of the band gap, capable of absorbing photons of low energies. We have carried out a comparative analysis of the nature and possibility of formation of the intermediate band in two compounds Ga4P3Ti and Ga3P4Ti in terms of density of states, electronic density, and atomic and orbital populations. We found that the intermediate band is formed only in one of these compounds. (C) 2003 American Institute of Physics.