Electrical properties of (SN)x films

The temperature dependence of the thermopower S and the conductivity σ of (SN)_x films has been investigated as a function of the substrate temperature during film deposition T_s. In contrast to the transport properties of SN_x films previously reported, films made with high T_s have metallic-like transport properties approaching those of (SN)_x crystals. For low substrate temperatures σ and S are found to increase strongly with rising temperature and thermopower values up to 0.9 mV/K are observed. This conduction behavior is explained by a heterogeneous model with areas having different electronic gaps. Annealing as well as decomposition effects suggest that the gap width is correlated to the (SN)_x chain length. No evidence was seen for superconductivity in these films.