The electronic structures of In4 Sn3 O12, In5 SnSbO12 and the intermediate solid solution In4+x Sn3-2x Sbx O12 have been studied by x-ray photoemission spectroscopy. The surfaces were found be consistently rich in indium and deficient in tin, with the extent of the deviation from bulk stoichiometry decreasing with increasing cosubstitution of In and Sb for Sn. We find that the valence band structure of the In4+x Sn3-2x Sbx O12 solid solution evolves with the degree of cosubstitution and shows well-defined features that arise from the hybridization of O 2p states with In 5s, Sn 5s, and Sb 5s states. We determine the fundamental electronic gaps of In4 Sn3 O12 and In5 SnSbO12 as 2.66 eV and 2.79 eV, respectively. © 2010 American Institute of Physics.
