THE DEPENDENCE OF THE DARK CONDUCTIVITY OF HYDROGENATED AMORPHOUS-SILICON FILMS ON THE HYDRIDE CONTENT

Dark conductivity and photoconductivity measurements on hydrogenated amorphous silicon (a-Si:H) films, prepared by saddle-field glow discharge and plasma-enhanced reactive evaporation, are correlated with the hydrogen content of these films. In particular, the dependence of the dark conductivity on the monohydride, polyhydride, and total bonded hydrogen content is studied. In addition, the dependence of the monohydride and polyhydride contents on the total bonded hydrogen content is investigated. The results are consistent with the hypothesis that it is the total amount of bonded hydrogen that determines the conductive properties of these films, rather than the proportion of polyhydride to monohydride sites. The monohydride and polyhydride contents of the films are compared with the predictions of a statistical model which appears to establish theoretical limits on the functional dependencies of these contents with respect to the total bonded hydrogen content.