ELECTRONIC-STRUCTURE AND ELECTRICAL-CONDUCTIVITY OF AMORPHOUS NI-SI ALLOY-FILMS

The NixSi100-x system forms a homogeneous amorphous phase over wide ra nges of composition (0 less than or equal to x less than or equal to 3 4 and 63 less than or equal to x less than or equal to 73) when the al loy is deposited on a substrate by sputtering at ambient temperature. The electrical conductivity of the amorphous alloy changes characteris tically with Ni concentration from a semiconductor-like temperature de pendence to a metallic one: the transition taking place between 10.4 a nd 16.6% Ni. UPS valence band spectra show that the density of states at the Fermi level is minimal below about 7% Ni, but emerges abruptly above this concentration. The relationship between the electrical tran sport properties and the electronic structure of the amorphous alloys is discussed in three characteristic regions of the Ni concentration.