Structural studies of tin-doped indium oxide (ITO) and In4Sn3O12

Structural changes in the indium oxide lattice due to doping with Sn4+ (ITO) were studied by Mossbauer spectroscopy, EXAFS, and neutron powder diffraction, There is a decrease in electrical conductivity as the tin content and oxygen partial pressure increase, which is related to a distortion in the first Sn-O shell, Doping with tin increases the oxygen/cation ratio and the lattice parameter and decreases the Sn-O distances, which disorders the host network, The low-conduction In4Sn3O12 phase precipitates when the tin content exceeds 6 at.%, In4Sn3O12 is rhombohedral (space group R (3) over bar, a = 9.4604(2) Angstrom, and c = 8.8584(2) Angstrom in a hexagonal basis), There is a cation ordering with octahedral sites fully occupied by tin, the tin sites being equivalent in both highly doped ITO and In4Sn3O12. (C) 1998 Academic Press.