PREPARATION AND CHARACTERIZATION OF ZN3P2-CD3P2 SOLID-SOLUTIONS

Solid solutions of Zn3P2-Cd3P2 systems of the type (ZnxCd1-x)3P2 have been prepared by direct reaction of the constituent elements (Zn, Cd, P) for values of x equal to 0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0. X-ray diffraction data indicate that all the systems crystallize in tetragonal (alpha) phase only, exhibiting preferred orientation along the (220) and (224) directions. The lattice parameters, a and c, and the interplanar spacing, d, vary linearly with x, obeying Vegard's law. The systems show minimum conductivity at room temperature for composition corresponding to x values in the range 0.4-0.6. Electrical conductivity for all systems is measured in the temperature range 100-450 K. In view of the estimated (low) values of the activation energy the conduction process in the different temperature regions has been attributed to the presence of shallow trapping levels in the systems.