A study of polycrystalline Cd(Zn, Mn)Te/Cds films and interfaces.

Polycrystalline films of CdZnTe ( x = 0-0.4) and CdMnTe ( x = 0-0.25) were grown by MBE and MOCVD, respectively, on CdS/SnO/glass substrates to investigate their feasibility for solar cell applications. The compositional uniformity and interface quality of the films were analyzed by x-ray diffraction, surface photovoltage, and Auger depth profile measurements to establish a correlation between growth conditions and lattice constant, atomic concentration, and bandgap of the ternary films. MBE-grown polycrystalline CdZnTe films showed a linear dependence between Zn/(Cd + Zn) beam flux ratio, Zn concentration in the film, and the bandgap. Polycrystalline CdZnTe films grown at 300° C showed good compositional uniformity in contrast to compositionally non-uniform CdMnTe films grown by MOCVD in the temperature range of 420-450° C. The MBE-grown CdZnTe interface also showed significantly less interdiffusion compared to the MOCVD-grown CdMnTe/CdS interface, where preferential exchange between Cd from the CdS layer and Mn from the CdMnTe film was observed. The compositional uniformity of MOCVD-grown polycrystalline CdMnTe films grown on CdS/SnO/glass substrates was found to be a strong function of the growth conditions as well as the Mn source. [ABSTRACT FROM AUTHOR]