Theoretical basis for zincblende to wurtzite CdS-phase transition

Cubic cadmium sulfide polycrystalline thin films were prepared by the chemical bath deposition technique. Upon thermal annealing (TA) in Ar + S-2 ambient, in the range 100-500 degrees C, the evolution of CdS from the metastable zincblende (ZB) structure to the stable wurtzite (W) phase can be monitored. From X-ray diffraction patterns the ZB and W lattice parameters were determined and from these the corresponding unit cell volumes. These volumes plotted vs TA were fitted to the slow adiabatic growth of a nucleation center model for metastable to stable modifications of a given crystal (Akhiezer ct ni., Sov. Phys. Solid State, 24, 1313, 1982). The theoretical model explains successfully the phase transition kinetics of CdS from the ZB to the W crystalline structure.