Cation distribution of the transparent conductor and spinel oxide solution Cd1+xIn2-2xSnxO4

The cation distribution in the transparent conducting oxide Cd1+xIn2-2xSnxO4 was investigated to determine if there is a correlation between structure and electronic properties. Combined Rietveld refinements of neutron and X-ray diffraction data and Sn-119 Mossbauer spectroscopic analysis were used to show that the cation distribution changed with x (0 less than or equal to x less than or equal to 0.7) from a primarily normal spinel (x=0) to an increasingly random spinel. CdIn2O4 quenched from 1175degreesC has an inversion parameter of 0.31 (i.e., (Cd0.69In0.31)(tet)(In1.69Cd0.31)O-oct(4)). The inversion parameter decreases to 0.27 as the quench temperature is lowered from 1175degreesC to 1000degreesC. The decrease in inversion parameter with temperature correlates with an increase in optical gap from 3.0 eV to 3.3 eV for specimens prepared at 1175degreesC and 800degreesC respectively. We show that this is a consequence of an increase in the fundamental band gap. (C) 2002 Elsevier Science.