Electrical, optical, and structural properties of tin-doped In2O3-M2O3 solid solutions (M = Y, Sc)

In2O3 crystallizes in the bixbyite, or C-type rare earth, structure (space group Ia3), as do the smaller lanthanide oxides (Tb-Lu) and the oxides of Y and Sc. Solid solutions of In2-xMxO3-delta (M = Y or Sc) with varying lattice parameters were prepared and doped with tin, Substitution of tin oxide into In2-xYxO3-delta results in the formation of the pyrochlore phase, Y2Sn2O7. The pyrochlore dominates the Y-In-Sn oxide ternary phase diagram and prevents the tin from donating charge carriers. Solid solutions in which M = Sc could be reacted with a limited amount of tin oxide without the formation of a second phase. The presence of increasing scandium results in decreasing conductivity with a corresponding increase in the optical band gap and percent transmission. (C) 2000 Academic Press.