Influence of annealing temperature on the opto-electronic characteristics of ZnTe electrodeposited semiconductors

Thin film ZnTe semiconductors for photovoltaic applications were prepared by electrodeposition in aqueous solution at - 0.75 V (SCE). X-ray diffraction analysis showed that polycrystalline ZnTe films were produced by annealing the deposits at 375 and 400°C. A filament-shaped morphology was observed in the electrodeposited samples, with a larger surface homogeneity for the films annealed at higher temperature. A direct energy gap of 2.3 eV at 400°C was found, in agreement with the literature. Sheet resistance, free carrier concentration and Hall mobility values were also determined. A decrease of majority carrier concentration and an increase of carrier mobility with the annealing temperature was related to the decrease of the level of crystallographic defects in the sample treated at 400°C. © 1997 Elsevier Science S.A.