High-sensitivity thin-film strain sensor

Abstract

Evaporated cadmium sulfide thin-film resistors have been fabricated which exhibit remarkable strain sensitivity. Electrodes are arranged in sandwich fashion so that electrons flow perpendicular to the plane of the CdS layer. The layers are doped and heat treated so that nominal unstrained resistivities are of the order of 3 × 105 Ω cm. Tensile and compressive strain in the plane of the film causes the resistance to increase and decrease, respectively, by as much as a factor of 15.