THE EFFECT OF HYDROGENATION ON THE ELECTRONIC-PROPERTIES OF AMORPHOUSSILICON-NICKEL ALLOYS NEAR THE METAL-INSULATOR-TRANSITION

The temperature dependence of the electrical conductivity of two sets of amorphous silicon-nickel alloys, one of which is hydrogenated, is p resented. The results have been analysed in an attempt to determine th e nature of the conduction processes. For metallic samples, evidence i s obtained for quantum interference mediated by inelastic scattering a nd also for the existence of electron-electron interactions. On the in sulating side of the metal-insulator transition, transport occurs in l ocalized states, but the results cannot be convincingly explained in t erms of conventional variable-range hopping theories, even when Coulom b effects are included. The effect of hydrogenation is to raise the me tal concentration required to reach the metallic state.