CURRENT FLUCTUATIONS AND SWITCHING EFFECTS IN HYDROGENATED AMORPHOUS-SILICON MOLYBDENUM MULTILAYER THIN-FILMS

Current-voltage characteristics and the temperature-dependent conducti vity have been investigated for multilayer samples consisting of nanom etre-size Mo clusters arranged in planes, which are separated by hydro genated amorphous Si sublayers 80nm thick. The samples show unique ele ctronic properties which are reported for the first time. A typical el ectric field of 80 V cm-1 applied to the samples with a coplanar elect rode configuration results in a switching from a semiconducting to a m etallic state with typical conductivities at room temperature of 10(-6 ) and 1 OMEGA-1 cm-1, respectively. The switching effect, which is rev ersible by thermal annealing at 450 K, is accompanied by chaotic curre nt fluctuations with a ratio of maximum to minimum current of typicall y a factor of three and in some cases up to three orders of magnitude. The temperature dependence of the conductivity in the metallic state is described by sigma = sigma0exp(-T0/T)1/2 with typically sigma0 = 3 OMEGA-1 cm-1 and T0 = 240 K.