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The hydrogenated amorphous silicon/nanodisperse metal (Simal) system - films of unique electronic properties

1996; Elsevier BV; Volume: 198-200; Linguagem: Inglês

10.1016/0022-3093(96)00050-6

1873-4812

T. Drüsedau, Andreas N. Panckow, F. Klabunde,

Silicon Nanostructures and Photoluminescence

The a-Si:H/metal systems (Simals) were prepared as a-Si:H/V/a-Si:H or a-Si:H/Mo/a-Si:H trilayers and multilayers of a-Si:H/Mo or a-Si:H/Ti by PCVD, sputtering and thermal evaporation, respectively. Structural investigations performed on these films by scanning force microscopy, cross-sectional TEM and X-ray techniques indicate that Simals contain metal nanoclusters and an intermixed silicon-metal phase. The temperature dependence of the conductivity is described by σ = σo exp[−(ToT)12] with To ranging 100 K to 4 × 104 K. An electric field, typical of 100 V/cm applied to the samples in a coplanar electrode configuration results in an increase of the conductivity at room temperature from 10−6 to 1 (Ω cm)−1, which is reversible by annealing. This switching is accompanied by large fluctuation of the current. The electrical behavior of the Simals is compared to in-situ measurements on Mo-films on a-Si:H.