Journal cover Journal topic
Journal of Sensors and Sensor Systems An open-access peer-reviewed journal
J. Sens. Sens. Syst., 7, 1-11, 2018
https://doi.org/10.5194/jsss-7-1-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular research article
09 Jan 2018
Granular metal–carbon nanocomposites as piezoresistive sensor films – Part 1: Experimental results and morphology
Günter Schultes1, Hanna Schmid-Engel1, Silvan Schwebke1, and Ulf Werner2 1Sensors and Thin Film Group, University of Applied Sciences, 66117 Saarbrücken, Germany
2Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
Abstract. We have produced granular films based on carbon and different transition metals by means of plasma deposition processes. Some of the films possess an increased strain sensitivity compared to metallic films. They respond to strain almost linearly with gauge factors of up to 30 if strained longitudinally, while in the transverse direction about half of the effect is still measured. In addition, the film's thermal coefficient of resistance is adjustable by the metal concentration. The influence of metal concentration was investigated for the elements Ni, Pd, Fe, Pt, W, and Cr, while the elements Co, Au, Ag, Al, Ti, and Cu were studied briefly. Only Ni and Pd have a pronounced strain sensitivity at 55 ± 5 at. % (atomic percent) of metal, among which Ni–C is far more stable. Two phases are identified by transmission electron microscopy and X-ray diffraction: metal-containing nanocolumns densely packed in a surrounding carbon phase. We differentiate three groups of metals, due to their respective affinity to carbon. It turns out that only nickel has the capability to bond and form a stable and closed encapsulation of GLC around each nanoparticle. In this structure, the electron transport is in part accomplished by tunneling processes across the basal planes of the graphitic encapsulation. Hence, we hold these tunneling processes responsible for the increased gauge factors of Ni–C composites. The other elements are unable to form graphitic encapsulations and thus do not exhibit elevated gauge factors.

Citation: Schultes, G., Schmid-Engel, H., Schwebke, S., and Werner, U.: Granular metal–carbon nanocomposites as piezoresistive sensor films – Part 1: Experimental results and morphology, J. Sens. Sens. Syst., 7, 1-11, https://doi.org/10.5194/jsss-7-1-2018, 2018.

Publications Copernicus
Short summary
This research is about future sensor devices for force, pressure, and weight. The core of such sensors for mechanical quantities is a thin film that reacts to deformation. We are developing new sensor films with higher output. Different compositions of metal containing carbon films are examined. Most preferable and stable films contain nickel and carbon. The microscopic film morphology is uncovered. Electron tunneling between nanoparticles is responsible for the very sensitive reaction.
This research is about future sensor devices for force, pressure, and weight. The core of such...
Share