Carbon Nanotube Micropillars for Strain Sensing

A miniaturized strain sensor based on carbon nanotube (CNTs) micropillars is presented. The micropillars consist of square shaped forests of oriented CNTs sitting on Pt electrodes. The study focused on the analysis of the electron transport mechanisms and their correlation with the device geometry and deformation modes for increasing compression states (up to nearly 80% axial compression). The electrical resistance was found to be nonlinearly related to the device deformation in compression and decompression (full cycle). All tested devices were sensitive to deformations for an extremely wide range of strain values (significantly higher than conventional sensors), with a superior sensitivity for ultra-small deformations which makes them ideal for nanoscale sensing. Finally, it is believed that the CNTs micropillars have the potential to lead to strain sensing devices with a tuneable sensitivity and sensing range capability since the electron transport properties were found to be influenced by the device geometry.