ELECTROMECHANICAL PROPERTIES OF THIN VO2 FILMS ON POLYIMIDE SUBSTRATES

VO//2 films have been produced on polyimide substrates by reactive electron beam evaporation followed by annealing post-treatment. Films with thicknesses of about 0. 5 mu m had a gauge factor about 100 times larger than that for conventional strain gauges. The temperature dependence of the resistivity may be explained in terms of a strain-sensitive semiconductor-metal transition in somewhat inhomogeneous VO//2. However, this model accounts neither for the film thickness dependence of the gauge factor nor for the fact that polyimide is superior to glass as a substrate material. It is conceivable that a partially pyrolyzed surface layer plays some role in polyimide foils.